A386473 a(0) = 1; a(n) = a(n-1) - Sum_{k=0..n-1} k * a(k) * a(n-1-k).

1, 1, 0, -1, 2, -2, -2, 19, -86, 418, -2552, 18998, -163316, 1576012, -16834822, 197132715, -2510394870, 34532581946, -510187846128, 8055800188338, -135366492426340, 2411644527944740, -45402443673062276, 900596080479785934, -18772361629663252956, 410214725824741352244

Offset

0,5

Links

Table of n, a(n) for n=0..25.

Formula

G.f. A(x) satisfies A(x) = 1/( 1 - x + x^2 * (d/dx A(x)) ).

Prog

(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=v[i]-sum(j=0, i-1, j*v[j+1]*v[i-j])); v;

Crossrefs

Sequence in context: A358633 A087238 A226935 * A099640 A140283 A067097

Adjacent sequences: A386470 A386471 A386472 * A386474 A386475 A386476

Keyword

sign

Author

Seiichi Manyama, Jul 22 2025

Status

approved