Sequences

a(n) = 9*2^n.

Shifts one place left under 5th-order binomial transform.

Shifts one place left under 6th-order binomial transform.

a(n) = 3*a(n-2) - a(n-4), a(0)=0, a(1)=1, a(2)=1, a(3)=4. Alternates Fibonacci (A000045) and Lucas (A000032) sequences for even and odd n.

Certain subgraphs of a directed graph (inverse binomial transform of A005321).

a(n) = 11*2^n.

Certain subgraphs of a directed graph.

Denominator of (binomial(2*n-2,n-1)/n!)^2.

Divisors of 20: a finite sequence associated with the Lie algebra A_4.

The number of n X n (0,1)-matrices with a 1-width of 1.

The number of n X n (0,1)-matrices with a 1-width of 2.

Random walks (binomial transform of A006054).

Number of walks of length 2n+6 in the path graph P_7 from one end to the other.

Number of walks of length 2n+7 in the path graph P_8 from one end to the other.

Number of walks of length 2n+8 in the path graph P_9 from one end to the other.

Random walks.

Number of non-neighborly combinatorial 3-manifolds.

Number of trivalent maps with n nodes.

Number of symmetric trivalent maps with n nodes.

a(n) = 13*2^n.

a(n) = 5*3^n.

Number of n-dimensional space groups in largest crystal class.

a(n) = 7*3^n.

Number of nonequivalent dissections of a polygon into n quadrilaterals by nonintersecting diagonals rooted at a cell up to rotation.

Number of nonequivalent dissections of a polygon into n quadrilaterals by nonintersecting diagonals up to rotation.

Number of nonequivalent dissections of a polygon into n quadrilaterals by nonintersecting diagonals rooted at a cell up to rotation and reflection.

Number of nonequivalent dissections of a polygon into n quadrilaterals by nonintersecting diagonals up to rotation and reflection.

Number of nonequivalent dissections of a polygon into n pentagons by nonintersecting diagonals rooted at a cell up to rotation.

Number of nonequivalent dissections of a polygon into n pentagons by nonintersecting diagonals up to rotation.

Number of nonequivalent dissections of a polygon into n pentagons by nonintersecting diagonals rooted at a cell up to rotation and reflection.

Number of nonequivalent dissections of a polygon into n pentagons by nonintersecting diagonals up to rotation and reflection.

Positive integers k repeated ceiling(k/3) + 1 times.

Primes formed by the initial digits of the decimal expansion of Pi.

Riordan numbers: a(n) = (n-1)*(2*a(n-1) + 3*a(n-2))/(n+1).

Alcuin's sequence: expansion of x^3/((1-x^2)*(1-x^3)*(1-x^4)).

Number of restricted 3 X 3 matrices with row and column sums n.

Number of partitions of a 2n-set into even blocks.

Minimal span of set of n elements with no 3-term arithmetic progression.

Minimal span of set of n elements with no 4-term arithmetic progression.

Minimal span of set of n elements with no 5-term arithmetic progression.

Minimal span of set of n elements with no 6-term arithmetic progression.

a(n) = 8*3^n.

a(n) = 10*3^n.

Expansion of g.f. (1 - 2*x)/(1 - 5*x).

a(0) = 1; a(n) = 4*5^(n-1) for n >= 1.

a(n) = 7*5^n.

a(n) = 3^n + 2^n - 1.

a(n) = 5^n - 2^n.

a(n) = 5^n - 3^n.

a(n) = (5^n - 3^n)/2.