Sequences

Cluster series for b.c.c. lattice.

Cluster series for cubic lattice.

Cluster series for diamond.

Number of ways to quarter a 2n X 2n chessboard.

Number of binary forests with n nodes.

Hex (or centered hexagonal) numbers: 3*n*(n+1)+1 (crystal ball sequence for hexagonal lattice).

Number of Hamiltonian graphs with n nodes.

Maximum of minimum total weight for threshold functions of n Boolean variables.

Weights of threshold functions.

Self numbers divisible by sum of their digits (or, self numbers which are also Harshad numbers).

Low-temperature series for spin-1/2 Ising ferromagnetic susceptibility on diamond.

Number of even permutations of length n with no fixed points.

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

Erroneous version of A006841.

The number of superpositions of cycles of order n of the groups E_3 and D_n.

The number of superpositions of cycles of order n of the groups S_3 and D_n.

Automorphic numbers: m^2 ends with m.

Endpoints (leaves) in rooted trees with n nodes.

Endpoints in trees with n nodes.

a(n) = a(n-1) + 2*a(n-3) with a(0)=a(1)=1, a(2)=3.

Expansion of 1/((1-x)*(1-2*x)*(1-x-2*x^3)).

a(n) = floor(n*(sqrt(5)+5)/2).

Expansion of (x-1)*(x^2-4*x-1)/(1-2*x)^2.

Numbers k such that A003231(A001950(k)) = A001950(A003231(k)).

Numbers k such that A003231(A001950(k)) = A001950(A003231(k)) - 1.

a(n) = Sum_{k=0..n} (-1)^(n-k) C(n,k)*C(k^2,n).

a(n) = Sum_{k=0..n} (-1)^(n-k) C(n,k)*C((k+1)^2, n).

Number of partially achiral planted trees with n nodes.

Number of rooted trees with n vertices in which vertices at the same level have the same degree.

Number of rooted planar trees with n non-root nodes: circularly cycling the subtrees at the root gives equivalent trees.

Number of partially achiral rooted trees.

Number of achiral rooted trees.

Number of compositions of n such that no two adjacent parts are equal (these are sometimes called Carlitz compositions).

Number of partially achiral trees with n nodes.

Number of unrooted achiral trees with n nodes.

Nearest integer to -4n/Bernoulli(2n).

Discriminants of real quadratic norm-Euclidean fields (a finite sequence).

Complement of A003248.

a(n) = A000201(A003234(n)) + n.

a(n) = A001950(A003234(n)) + 1.

The number m such that A001950(m) = A003231(A003234(n)).

Complement of A003250.

The number m such that A003251(m) = A003231(n).

Complement of A003252.

The number m such that A003233(m) = A005206(A003234(n)).

Complement of A003254.

a(n) is the number m such that A242094(m) = A001950(n).

Complement of A003256.

The number m such that c'(m) = A005206(A003231(n)), where c'(m) = A249115(m) is the m-th positive integer not in A003231.

Complement of A003258.