Sequences

Expansion of q^(-1/2) * (eta(q) * eta(q^2))^4 in powers of q.

Glaisher's chi_4(n).

Expansion of eta(q^5)*eta(q^19).

Expansion of eta(q^7)*eta(q^17).

Expansion of eta(q^9)*eta(q^15).

Expansion of q^-1 * eta(q^10) * eta(q^14) in powers of q^2.

Expansion of eta(q^11)*eta(q^13).

Expansion of eta(q^3) * eta(q^5) * eta(q^6) * eta(q^10) in powers of q.

Expansion of (eta(q^5)*eta(q^7))^2.

Expansion of (eta(q^3)*eta(q^5))^3 in powers of q.

Chebyshev even-indexed U-polynomials evaluated at sqrt(7)/2.

Number of n-polyplets (polyominoes connected at edges or corners); may contain holes.

Number of achiral triangular n-ominoes (n-iamonds) (holes are allowed).

Triangular polyominoes (n-iamonds) without bilateral symmetry (holes are allowed).

Number of achiral hexagonal polyominoes with n cells.

Number of n-celled polyhexes (hexagonal polyominoes) without bilateral symmetry.

Number of achiral polyominoes with n cells.

Number of chiral pairs of polyominoes with n cells.

Numbers that are the product of an even number of distinct primes.

Numbers that have an odd number of distinct prime divisors.

Numbers with an even number of distinct prime factors.

Numbers k such that the number of divisors of k! divides the number of divisors of (2k)!.

Number of n-celled one-sided polyplets.

Number of n-celled polyplets having bilateral symmetry.

Number of n-celled polyplets without bilateral symmetry.

Cycle-path coverings of a family of digraphs.

Catalan's triangle with right border removed (n > 0, 0 <= k < n).

Backwards shallow diagonal sums of Catalan triangle A009766.

a(n) is the smallest number k such that k*2^(2^n) + 1 is prime.

Scaled Chebyshev U-polynomials evaluated at sqrt(7)/2.

Minimal determinant of any n-dimensional even lattice.

Number of n-point nonisomorphic relations with no symmetry.

Number of nonisomorphic relations with a nontrivial symmetry.

Number of connected nonisomorphic relations with no symmetry.

Number of nonisomorphic groupoids with no symmetry.

Number of nonisomorphic groupoids with a nontrivial symmetry.

Number of nonisomorphic idempotent groupoids.

Number of nonisomorphic idempotent groupoids with no symmetry.

Number of nonisomorphic idempotent groupoids with a nontrivial symmetry.

Number of nonisomorphic groupoids with no idempotents.

Number of nonisomorphic groupoids with no idempotents and no symmetry.

Number of nonisomorphic groupoids with no idempotents and a nontrivial symmetry.

Number of nonisomorphic groupoids with 1 idempotent.

Number of nonisomorphic groupoids with 1 idempotent and a nontrivial symmetry.

Number of nonisomorphic commutative groupoids with no symmetry.

Number of nonisomorphic commutative groupoids with a nontrivial symmetry.

Number of nonisomorphic commutative idempotent groupoids.

Number of nonisomorphic commutative idempotent groupoids with no symmetry.

Number of nonisomorphic commutative idempotent groupoids with a nontrivial symmetry.

Number of nonisomorphic commutative groupoids with no idempotents.