Sequences

Triangulations of the disk G_{n,1}.

Triangulations of the disk G_{n,2}.

Number of unrooted triangulations of a disk that have reflection symmetry with n interior nodes and 3 nodes on the boundary.

Number of unrooted triangulations of the disk with n interior nodes and 3 nodes on the boundary.

Number of different keys with n cuts, depths between 1 and 7 and depth difference at most 1 between adjacent cut depths.

An infinite coprime sequence defined by recursion.

An infinite coprime sequence defined by recursion.

a(n) = floor(n(n+2)(2n+1)/8).

Number of bicoverings of an n-set.

Erroneous version of A020554.

Number of partial permutations of an n-set; number of n X n binary matrices with at most one 1 in each row and column.

Number of 3 X 3 X 3 arrays M_ijk (1 <= i,j,k <= 3) with entries satisfying 0 <= M_ijk <= n and all line sums equal to n.

Rotatable partitions.

Number of rotatable partitions of [n].

Number of inequivalent n X n binary matrices, where equivalence means permutations of rows or columns.

Number of incidence matrices: n X (n+1) binary matrices under row and column permutations.

a(n) = Fibonacci(n+1) mod n.

Number of 3 X n binary matrices up to row and column permutations.

Number of n X (n+2) binary matrices.

Number of equivalence classes of binary sequences of period n.

Number of equivalence classes of binary sequences of primitive period n.

Numbers k such that (k^2 + 1)/2 is prime.

Numbers k such that (4*k^2 + 1)/5 is prime.

Numbers k such that (k^2 + 1)/10 is prime.

Remove squares!

Related to Euler numbers, expansion of e.g.f. sec(x)*tan^2(x).

Apéry numbers: a(n) = n^2*C(2n,n).

a(n) = Sum_{j=0..n} (n+j)*binomial(n+j,j).

Coefficients for extrapolation.

a(n) = ((2*n-1)!/(2*n!*(n-2)!))*((n^3-3*n^2+2*n+2)/(n^2-1)).

Number of tree-rooted bridgeless planar maps with two vertices and n faces.

Logarithmic numbers: expansion of the e.g.f. -log(1-x) * e^(-x).

Logarithmic numbers.

Sum of logarithmic numbers.

Sum of logarithmic numbers.

Sum of logarithmic numbers.

Sum of logarithmic numbers.

Logarithmic numbers.

Sum of logarithmic numbers.

Sum of logarithmic numbers.

Sum of logarithmic numbers.

Sum of logarithmic numbers.

a(n) = Fibonacci(n-1) mod n.

Coefficients of elliptic function sn.

Related to coefficient of m in Jacobi elliptic function cn(z, m).

Number of bipartite partitions of n white objects and 6 black ones.

Number of bipartite partitions of n white objects and 7 black ones.

Number of bipartite partitions of n white objects and 8 black ones.

Number of bipartite partitions of n white objects and 9 black ones.

Number of bipartite partitions of n white objects and 10 black ones.