20640

Appears in sequences

• [ Sum{(sqrt(j+1)-sqrt(i+1))^3} ], 1 <= i < j <= n.at n=48A025223
• Theta series of 8-d 5-modular lattice Q_8(1) with det 625 and minimal norm 4.at n=13A028976
• Number of labeled connected graphs with n nodes such that complement is also connected.at n=5A054913
• Number of primitive (period n) bracelets using a maximum of six different colored beads.at n=6A056347
• Number of step cyclic shifted sequence structures using a maximum of three different symbols.at n=14A056430
• Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,27.at n=7A064250
• Expansion of 1/(1-2*x-2*x^2+2*x^3).at n=11A077937
• Triangle read by rows: T(n,k) = number of unique-valued sequences of length k, n >= 1, 1 <= k <= 2n-3, in the symmetric group S_n.at n=8A097635
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 6 and 9.at n=19A136905
• Strongly refactorable numbers: numbers n such that if n is divisible by d, it is divisible by the number of divisors of d.at n=27A141586
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 1), (-1, 1, 1), (1, 0, -1), (1, 0, 1), (1, 1, 1)}.at n=7A151028
• A triangle sequence derived from setting an Euler numbers A122045 generalization equal to the MacMahon numbers A060187 to get a generating function expansion: p(x,t) = (exp(t)* (1 - exp(x))* x)/(exp(2 t + t x) + exp(t)* x - exp(t*x)* x).at n=46A178234
• Numbers of the form p^5*q*r*s where p, q, r, and s are distinct primes.at n=23A179704
• Numbers n such that n^8 + 1 and (n + 2)^8 + 1 are both prime.at n=41A217972
• 4-level binary fanout graph coloring a rectangular array: number of nX3 0..14 arrays where 0..14 label nodes of a graph with edges 0,1 1,3 3,5 3,6 1,4 4,7 4,8 0,2 2,9 9,11 9,12 2,10 10,13 10,14 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.at n=3A223444
• 4-level binary fanout graph coloring a rectangular array: number of nX4 0..14 arrays where 0..14 label nodes of a graph with edges 0,1 1,3 3,5 3,6 1,4 4,7 4,8 0,2 2,9 9,11 9,12 2,10 10,13 10,14 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.at n=2A223445
• T(n,k)=4-level binary fanout graph coloring a rectangular array: number of nXk 0..14 arrays where 0..14 label nodes of a graph with edges 0,1 1,3 3,5 3,6 1,4 4,7 4,8 0,2 2,9 9,11 9,12 2,10 10,13 10,14 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.at n=17A223449
• T(n,k)=4-level binary fanout graph coloring a rectangular array: number of nXk 0..14 arrays where 0..14 label nodes of a graph with edges 0,1 1,3 3,5 3,6 1,4 4,7 4,8 0,2 2,9 9,11 9,12 2,10 10,13 10,14 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.at n=18A223449
• Number of non-equivalent ways to choose two points in an equilateral triangle grid of side n.at n=30A227327
• a(n) = k, index of A165959(k) at record values.at n=16A230146