A124542 Row 2 of rectangular table A124540; equals the self-convolution of A124532 (row 2 of table A124530).

1, 2, 7, 26, 107, 486, 2398, 12668, 70863, 416304, 2552490, 16254406, 107095090, 727834866, 5089682472, 36548625188, 269065010063, 2027942075946, 15630423416331, 123079853443384, 989356860469923, 8112792202324232

Offset

0,2

Comments

In table A124540, the g.f. of row n, R_n(y), simultaneously satisfies: R_n(y) = [ Sum_{k>=0} y^k*R_k(y)^n ]^n for n>=0.

Links

Table of n, a(n) for n=0..21.

Prog

(PARI) {a(n)=local(R); R=vector(n+3, r, vector(n+3, c, 1)); for(i=0, n+2, for(r=0, n+2, R[r+1]=Vec(sum(c=0, n, x^c*Ser(R[c+1])^(r*c)+O(x^(n+1)))))); Vec(Ser(R[3])^2+O(x^(n+1)))[n+1]}

Crossrefs

Cf. A124532; A124540 (table); other rows: A124531, A124543, A124544, A124545, A124546.

Sequence in context: A367236 A006603 A080244 * A003447 A150569 A150570

Adjacent sequences: A124539 A124540 A124541 * A124543 A124544 A124545

Keyword

nonn

Author

Paul D. Hanna, Nov 05 2006

Status

approved