Sequences

A006318(n) - 1.

One half of 9-factorial numbers.

One third of 9-factorial numbers.

a(n) contains n digits (either '3' or '4') and is divisible by 2^n.

Period of continued fraction for square root of n-th squarefree integer.

Fourier coefficients of E_{0,4}.

One quarter of 9-factorial numbers.

One fifth of 9-factorial numbers.

Sizes of successive shells in hexagonal (or A_2) lattice.

One sixth of 9-factorial numbers.

One seventh of 9-factorial numbers.

One eighth of 9-factorial numbers.

One ninth of 9-factorial numbers.

Expansion of 1/(1-81*x)^(1/9), related to 9-factorial numbers A045756.

Constant term of (normalized Delta)^(-n).

Number of times that i and 2n-i are both prime, for i = 1, ..., 2n-1.

Greatest integer that is <= the sum of the n-th powers of its digits.

First differences of A002002.

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

Erroneous version of A323468.

For n >= 7, max(A151799(n), 2*A151799(floor((n-1)/2))).

For n >= 6, max( prevprime(n), 2*prevprime(floor(n/2))).

Numbers k such that k <= d(k)^2, where d() = number of divisors (A000005).

Numbers k such that k >= d(k)^2, where d(k) is the number of divisors of k.

Numbers k such that k > d(k)^2, where d(k) is the number of divisors of k.

Fourier coefficients of E_{gamma,2}*E_{0,4}.

Fourier coefficients of E_{gamma,2}^2*E_{0,4}.

a(n) = 2^n - C(n,0) - C(n,1) - ... - C(n,5).

a(n) = 2^n - C(n,0) - C(n,1) - ... - C(n,6).

a(n) = 2^n - C(n,0) - C(n,1) - ... - C(n,7).

a(n) = 2^n - C(n,0) - C(n,1) - ... - C(n,8).

a(n) = 2^n - C(n,0)- ... - C(n,9).

Replace any decimal digit '1' with '2' and vice versa.

Exchange 2 and 3.

Inverse binomial transform of A002054.

Numbers with two representations as cube + fifth power.

Denominators of alternating sum transform (PSumSIGN) of Harmonic numbers H(n) = A001008/A002805.

Numerators of alternating sum transform (PSumSIGN) of Harmonic numbers H(n) = A001008/A002805.

E.g.f. satisfies A(x) = x*(1+A(A(x))), A(0)=0.

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

Number of labeled rooted connected graphs where every block is a complete graph.

Number of sets of rooted connected graphs where every block is a complete graph.

Number of connected graphs on n unlabeled nodes where every block is a complete graph.

Number of forests of identical trees.

Number of forests of different trees.

Number of asymmetric forests with n nodes.

Numbers k such that 2^k does not contain the digit 1 (probably finite).

Numbers k such that 2^k does not contain the digit 3 (probably finite).

Numbers k such that 2^k does not contain the digit 4 (probably finite).

Numbers k such that 2^k does not contain the digit 5 (probably finite).