Sequences

Number of totally isotropic spaces of index n in orthogonal geometry of dimension 2n.

Total number of self-dual binary codes of length 2n. Totally isotropic spaces of index n in symplectic geometry of dimension 2n.

Total number of doubly-even self-dual binary codes of length 8n.

Triangle T(n,m) = Sum_{k=0..m} Catalan(n-k)*Catalan(k).

Order of general affine group over GF(2), AGL(n,2).

a(n) = (2^n - 1)!.

a(n) = (2^n-2)!.

a(n) = (Product_{j=1..n-1} (2^j-1)) * 2^binomial(n+1,2).

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

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

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

Smallest prime that is simultaneously of forms x^2 + m*y^2 for m = 1, ..., n.

Numbers that have only the straight digits {1, 4, 7}.

Numbers that have only curved digits {0, 3, 6, 8, 9} or digits that are both curved and linear {2, 5}.

Squares of (odd numbers not divisible by 5).

Triangle read by rows: T(n,m) = Sum Catalan(n-k)*Catalan(k), k=0..m.

Expansion of Product_{m>0} (1+q^m)^(m(m+1)/2).

Concatenate rows of triangle in A028364 (removing duplicates).

a(n) = 6*(n+1)*(2*n+6)!/((n+3)!*(n+5)!).

a_n = - sum_{i=1..n-1} C(i+1, n-i) (-1)^(n-i) a_i.

Weight distribution of [ 17,9,5 ] binary quadratic-residue code.

Weight distribution of [ 31,16,7 ] binary BCH and quadratic-residue codes.

Weight distribution of [ 31,15,8 ] binary quadratic-residue code.

Weight distribution of [ 47,24,11 ] binary quadratic-residue code.

Weight distribution of [ 47,23,12 ] binary quadratic-residue code.

Numbers k such that k*(3k-1)/2 is a pentagonal palindrome.

a(n) = n + (n+1)^2.

Good primes (version 2): prime(n) such that prime(n)^2 > prime(n-i)*prime(n+i) for all 1 <= i <= n-1.

The 5x + 1 sequence beginning at 7.

Nearest integer to 3n/4 unless that is an integer, when 3n/2.

a(n) = n - floor(sqrt(n)).

a(n) = n + floor(sqrt(n)).

Iterate the map in A006368 starting at 8.

Iterate the map in A006369 starting at 8.

Iterate the map in A006368 starting at 14.

Iterate the map in A006369 starting at 14.

Start at n and iterate the map in A006368; a(n) is the smallest number in the trajectory.

When map in A006368 is iterated, all numbers fall into cycles; order cycles by smallest entry; a(n) is smallest entry in n-th cycle (some cycles are infinite).

a(n) = 2^n - 4.

a(n) = (2^n + 1)^2.

The (2^n+1)-th triangular number (cf. A000217).

Number of types of Boolean functions of n variables under a certain group.

Number of types of Boolean functions of n variables under a certain group.

Number of types of Boolean functions of n variables under a certain group.

Number of equivalence classes of Boolean functions of n variables under action of M(n,2).

Number of types of Boolean functions of n variables under a certain group.

Number of equivalence classes of Boolean functions of n variables under action of LSD(n,2).

Number of types of Boolean functions of n variables under a certain group.

Number of types of Boolean functions of n variables under a certain group.

Number of types of Boolean functions of n variables under a certain group.