A169960 a(n) = binomial(11*n,n).

1, 11, 231, 5456, 135751, 3478761, 90858768, 2404808340, 64276915527, 1731030945644, 46897636623981, 1276749965026536, 34898565177533200, 957150015393611193, 26327386978706181060, 725971390105457325456, 20062118235172477959495, 555476984964439251664995

Offset: 0

Author

N. J. A. Sloane, Aug 07 2010

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200

Crossrefs

binomial(k*n,n): A000984 (k = 2), A005809 (k = 3), A005810 (k = 4), A001449 (k = 5), A004355 (k = 6), A004368 (k = 7), A004381 (k = 8), A169958 - A169961 (k = 9 thru 12).

Programs

Magma

[Binomial(11*n, n): n in [0..20]]; // Vincenzo Librandi, Aug 07 2014

Mathematica

Table[Binomial[11 n, n], {n, 0, 20}] (* Vincenzo Librandi, Aug 07 2014 *)

Formula

a(n) = C(11*n-1,n-1)*C(121*n^2,2)/(3*n*C(11*n+1,3)), n>0. - Gary Detlefs, Jan 02 2014

From Peter Bala, Feb 21 2022: (Start)

The o.g.f. A(x) is algebraic: (1 - A(x))*(1 + 10*A(x))^10 + (11^11)*x*A(x)^11 = 0.

Sum_{n >= 1} a(n)*( x*(10*x + 11)^10/(11^11*(1 + x)^11) )^n = x. (End)