A171486 - OEIS

A171486

Riordan array (f(x), x*f(x)) where f(x) is the g.f. of A033321.

1, 1, 1, 2, 2, 1, 6, 5, 3, 1, 21, 16, 9, 4, 1, 79, 58, 31, 14, 5, 1, 311, 224, 117, 52, 20, 6, 1, 1265, 900, 465, 205, 80, 27, 7, 1, 5275, 3720, 1910, 840, 330, 116, 35, 8, 1, 22431, 15713, 8034, 3532, 1396, 501, 161, 44, 9, 1, 96900, 67522, 34419, 15136, 6015, 2190

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

0,4

COMMENTS

Equal to B*A065600 = A171224*B where B = A007318 ; equal to B*A039598*B^(-2).

LINKS

Table of n, a(n) for n=0..60.

FORMULA

Sum_{k, 0<=k<=n} T(n,k)*x^k = A117641(n), A033321(n), A007317(n+1), A002212(n+1), A026378(n+1) for x = -1, 0, 1, 2, 3 respectively.

T(n,k) = T(n-1,k-1) + T(n-1,k) + sum_{i, i>=0} T(n-1,k+1+i)*2^i. - Philippe Deléham, Feb 23 2012

EXAMPLE

Triangle begins :