A054442 Second convolution of A001405 (central binomial numbers).

1, 3, 9, 22, 54, 123, 281, 618, 1362, 2934, 6330, 13452, 28620, 60243, 126921, 265282, 554874, 1153506, 2399390, 4966740, 10286196, 21219038, 43790154, 90076452, 185353204, 380364108, 780786516, 1599015192, 3275589144

Offset

0,2

Links

Table of n, a(n) for n=0..28.

Formula

a(2*k)= -3*2^(2*k+1)+binomial(2*(k+1), k+1)*(4*k+7)/2, a(2*k+1)= -3*4^(k+1)+binomial(2*(k+2), k+2)*(2*k+5)/2, k >= 0.

a(n)= A054336(n+2, 2) (third column of convolution triangle). G.f.: (1/(1-x-x^2*c(x^2)))^3, with c(x) the g.f. for the Catalan numbers A000108.

Crossrefs

Cf. A000108, A001405, A054336, A045621.

Sequence in context: A202882 A350105 A336511 * A354648 A192663 A114697

Adjacent sequences: A054439 A054440 A054441 * A054443 A054444 A054445

Keyword

easy,nonn

Author

Wolfdieter Lang, Mar 27 2000

Status

approved