Sequences
392,541 sequences
- a(n) = Sum_{k=0..8} binomial(n,k).A008861
a(n) = Sum_{k=0..8} binomial(n,k).
- a(n) = Sum_{k=0..9} binomial(n,k).A008862
a(n) = Sum_{k=0..9} binomial(n,k).
- a(n) = Sum_{k=0..10} binomial(n,k).A008863
a(n) = Sum_{k=0..10} binomial(n,k).
- a(n) = prime(n) + 1.A008864
a(n) = prime(n) + 1.
- a(n) = n^2 - 2.A008865
a(n) = n^2 - 2.
- Prime(A052928(n+1)) + (-1)^n* prime(A109613(n)).A008866
Prime(A052928(n+1)) + (-1)^n* prime(A109613(n)).
- Triangle of truncated triangular numbers: k-th term in n-th row is number of dots in hexagon of sides k, n-k, k, n-k, k, n-k.A008867
Triangle of truncated triangular numbers: k-th term in n-th row is number of dots in hexagon of sides k, n-k, k, n-k, k, n-k.
- Order of simple Chevalley group E_8 (q), q = prime power.A008868
Order of simple Chevalley group E_8 (q), q = prime power.
- Order of universal Chevalley group E_7 (q), q = prime power.A008869
Order of universal Chevalley group E_7 (q), q = prime power.
- Order of simple Chevalley group E_7 (q), q = prime power.A008870
Order of simple Chevalley group E_7 (q), q = prime power.
- Order of universal Chevalley group E_6 (q), q = prime power.A008871
Order of universal Chevalley group E_6 (q), q = prime power.
- Order of simple Chevalley group E_6 (q), q = prime power.A008872
Order of simple Chevalley group E_6 (q), q = prime power.
- 3x+1 sequence starting at 97.A008873
3x+1 sequence starting at 97.
- 3x+1 sequence starting at 63.A008874
3x+1 sequence starting at 63.
- 3x+1 sequence starting at 95.A008875
3x+1 sequence starting at 95.
- 3x+1 sequence starting at 81.A008876
3x+1 sequence starting at 81.
- 3x+1 sequence starting at 57.A008877
3x+1 sequence starting at 57.
- 3x+1 sequence starting at 39.A008878
3x+1 sequence starting at 39.
- 3x+1 sequence starting at 87.A008879
3x+1 sequence starting at 87.
- 3x + 1 sequence starting at 33.A008880
3x + 1 sequence starting at 33.
- a(n) = Product_{j=0..5} floor((n+j)/6).A008881
a(n) = Product_{j=0..5} floor((n+j)/6).
- 3x+1 sequence starting at 99.A008882
3x+1 sequence starting at 99.
- 3x+1 sequence starting at 51.A008883
3x+1 sequence starting at 51.
- 3x+1 sequence starting at 27.A008884
3x+1 sequence starting at 27.
- Aliquot sequence starting at 30.A008885
Aliquot sequence starting at 30.
- Aliquot sequence starting at 42.A008886
Aliquot sequence starting at 42.
- Aliquot sequence starting at 60.A008887
Aliquot sequence starting at 60.
- Aliquot sequence starting at 138.A008888
Aliquot sequence starting at 138.
- Aliquot sequence starting at 150.A008889
Aliquot sequence starting at 150.
- Aliquot sequence starting at 168.A008890
Aliquot sequence starting at 168.
- Aliquot sequence starting at 180.A008891
Aliquot sequence starting at 180.
- Aliquot sequence starting at 276.A008892
Aliquot sequence starting at 276.
- Number of equilateral triangles formed by triples of points taken from a hexagonal chunk of side n in the hexagonal lattice.A008893
Number of equilateral triangles formed by triples of points taken from a hexagonal chunk of side n in the hexagonal lattice.
- 3x - 1 sequence starting at 36.A008894
3x - 1 sequence starting at 36.
- The 3x-1 map: a(n) = n/2 if n is even, 3n-1 if n is odd.A008895
The 3x-1 map: a(n) = n/2 if n is even, 3n-1 if n is odd.
- 3x - 1 sequence starting at 66.A008896
3x - 1 sequence starting at 66.
- x->x/2 if x even, x->3x-1 if x odd.A008897
x->x/2 if x even, x->3x-1 if x odd.
- Trajectory of 84 under the map x -> x/2 for x even, x -> 3x - 1 for x odd.A008898
Trajectory of 84 under the map x -> x/2 for x even, x -> 3x - 1 for x odd.
- x -> x/2 if x even, x -> 3x - 1 if x odd.A008899
x -> x/2 if x even, x -> 3x - 1 if x odd.
- x->x/2 if x even, x->3x-1 if x odd.A008900
x->x/2 if x even, x->3x-1 if x odd.
- x->x/2 if x even, x->3x-1 if x odd.A008901
x->x/2 if x even, x->3x-1 if x odd.
- x->x/2 if x even, x->3x-1 if x odd.A008902
x->x/2 if x even, x->3x-1 if x odd.
- x->x/2 if x even, x->3x-1 if x odd.A008903
x->x/2 if x even, x->3x-1 if x odd.
- a(n) is the final nonzero digit of n!.A008904
a(n) is the final nonzero digit of n!.
- Leading digit of n!.A008905
Leading digit of n!.
- Number of digits in n! excluding final zeros.A008906
Number of digits in n! excluding final zeros.
- Number of legal tic-tac-toe (or noughts and crosses) positions after n plays, up to rotation and reflection.A008907
Number of legal tic-tac-toe (or noughts and crosses) positions after n plays, up to rotation and reflection.
- a(n) = (1 + number of halving and tripling steps to reach 1 in the Collatz (3x+1) problem), or -1 if 1 is never reached.A008908
a(n) = (1 + number of halving and tripling steps to reach 1 in the Collatz (3x+1) problem), or -1 if 1 is never reached.
- Join 2n points on a line with n arcs above the line; form graph with the arcs as nodes, joining 2 nodes when the arcs cross. a(n) is the number of cases in which the graph is a path.A008909
Join 2n points on a line with n arcs above the line; form graph with the arcs as nodes, joining 2 nodes when the arcs cross. a(n) is the number of cases in which the graph is a path.
- Join 2n points on a line with n arcs above the line; form graph with the arcs as nodes, joining 2 nodes when the arcs cross. a(n) is the number of cases in which the graph is symmetric about middle and has no isolated nodes.A008910
Join 2n points on a line with n arcs above the line; form graph with the arcs as nodes, joining 2 nodes when the arcs cross. a(n) is the number of cases in which the graph is symmetric about middle and has no isolated nodes.