Sequences

a(n) = number of special odd permutations of 2*n+1.

Number of complete mappings of the cyclic group Z_{2n+1}.

Permanent of Schur's matrix of order 2n+1.

Coefficients in expansion of permanent of infinite tridiagonal matrix shown below.

Number of partitions of n into parts 5k+1 or 5k+4.

a(n) = 4^floor(n/2)*a(n-1) - a(n-2), for n >= 2, with a(0) = a(1) = 1.

Expansion of the reciprocal of the g.f. defining A039924.

Continued fraction for fifth root of 3.

Continued fraction for fifth root of 4.

High-temperature series for spin-1/2 Ising magnetic susceptibility on diamond structure.

Number of rooted trees with n nodes and omega-valency 1.

Strict sense ballot numbers: n candidates, k-th candidate gets k votes.

Number of Hamiltonian rooted triangulations with n internal nodes and 3 external nodes.

Number of Hamiltonian rooted triangulations with n internal nodes and 4 external nodes.

One of the basic cycles in the x->3x-1 (x odd) or x/2 (x even) problem.

Value of an urn with n balls of type -1 and n+2 balls of type +1.

Value of an urn with n balls of type -1 and n+1 balls of type +1.

Value of an urn with n balls of type -1 and n balls of type +1.

Number of driving-point impedances of an n-terminal network.

Number of transfer impedances of an n-terminal network.

Impedances of an n-terminal network.

Order of Monster simple group.

Sum of squares of digits of n.

Order of simple Chevalley group E_8(2).

Orders of Weyl groups of type E_n.

n! is a nontrivial product of factorials. It is conjectured that the list is complete.

Loeschian numbers: numbers of the form x^2 + xy + y^2; norms of vectors in A2 lattice.

Write n in base 3 and juxtapose.

Nearest integer to 24*(2^n - 1)/n.

Number of coprime chains with largest member n.

Number of coprime chains with largest member prime(n).

Minimal number of arcs whose reversal yields a transitive tournament.

Largest subset of 3 X 3 X ... X 3 cube (in n dimensions) with no 3 points collinear.

a(2*n) = floor( 17*2^n/14 ), a(2*n+1) = floor( 12*2^n/7 ).

Positions of letter a in the tribonacci word abacabaabacababac... generated by a->ab, b->ac, c->a (cf. A092782).

Positions of letter b in the tribonacci word abacabaabacababac... generated by a->ab, b->ac, c->a (cf. A092782).

Positions of letter c in the tribonacci word abacabaabacababac... generated by a->ab, b->ac, c->a (cf. A092782).

Primes p with a Fibonacci primitive root g, i.e., such that g^2 = g + 1 (mod p).

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

a(n) = Sum_{k=0..n} k!*(n - k)!.

Fibonomial Catalan numbers.

Beatty sequence for 1+sqrt(2); a(n) = floor(n*(1+sqrt(2))).

A Beatty sequence: a(n) = floor(n*(1+1/sqrt(2))).

a(n) = integer nearest n*(1+sqrt(2)).

Centered 12-gonal numbers, or centered dodecagonal numbers: numbers of the form 6*k*(k-1) + 1.

Number of ways to halve an n X n chessboard.

A self-generating sequence (see Comments for definition).

A self-generating sequence (see Comments in A003156 for the definition).

A self-generating sequence (see Comments in A003156 for the definition).

Numbers whose binary representation ends in an even number of zeros.