Sequences

a(n) = round(10*log_2(n)).

a(n) = ceiling(10*log_2(n)).

a(n) = floor(100*log_2(n)).

a(n) = round(100*log_2(n)).

a(n) = ceiling(100*log_2(n)).

a(n) = floor(1000*log_2(n)).

a(n) = round(1000*log_2(n)).

a(n) = ceiling(1000*log_2(n)).

a(n) = floor(10000*log_2(n)).

a(n) = round(10000*log_2(n)).

a(n) = ceiling(10000*log_2(n)).

1, 3 and the nonnegative even numbers.

1, 3, 5 and the nonnegative even numbers.

0 together with odd numbers.

0, 2 and the odd numbers.

1 together with nonnegative even numbers.

0, 2, 4 and the odd numbers.

1 together with positive even numbers.

1, 3 and the positive even numbers.

1, 3, 5 and the positive even numbers.

2 together with the odd numbers (essentially the result of the first stage of the sieve of Eratosthenes).

2, 4 and the odd numbers.

a(n) = n*(n+1)^2*(n+2)^2/12.

Least positive multiple of n written in base 3 using only 0 and 1.

Least positive multiple of n written in base 4 using only 0 and 1.

Least positive multiple of n written in base 5 using only 0 and 1.

Least positive multiple of n written in base 6 using only 0 and 1.

Least positive multiple of n written in base 7 using only 0 and 1.

Least positive multiple of n written in base 8 using only 0 and 1.

Least positive multiple of n written in base 9 using only 0 and 1.

Least positive multiple of n that when written in base 10 uses only 0's and 1's.

Expansion of (1 + 2*x + x^2)/(1 - 10*x + x^2).

Expansion of (1+x)^2/(1-18*x+x^2).

Expansion of (1+2*x+x^2)/(1-26*x+x^2).

Expansion of (1+2*x+x^2)/(1-34*x+x^2).

Expansion of (1+2*x+x^2)/(1-42*x+x^2).

Expansion of g.f. (1+2*x+x^2)/(1-50*x+x^2).

Expansion of (1+2*x+x^2)/(1-58*x+x^2).

Expansion of (1+2*x+x^2)/(1-66*x+x^2).

Expansion of (1+2*x+x^2)/(1-74*x+x^2).

Number of symmetric irreducible diagrams with 2n nodes.

Second-order Eulerian numbers <<n,2>>.

a(n) = n^2*(n+1)^2*(n+2)/12.

a(n) = binomial(2*n-2,n-1)/n - 2^(n-1) + n.

Number of nonseparable planar tree-rooted maps with n edges.

Simple triangulations of a disk: column 4 of square array in A210664.

Rook polynomials.

Number of permutations p of [n] such that (n-p(i)+i) mod n >= 4 for all i.

Hit polynomials, coefficient of y in N_n(y).

Hit polynomials, coefficient of y^2 in N_n(y).