A385287 a(0) = 1, a(1) = 0; a(n) = a(n-2) + Sum_{k=0..n-1} k * a(k) * a(n-1-k).

1, 0, 1, 2, 7, 32, 177, 1148, 8535, 71552, 668037, 6877742, 77448741, 947342072, 12512378625, 177525399952, 2693306735145, 43516930747192, 746123462304725, 13531269497675506, 258807528403312427, 5206929233591435496, 109929366336996502793, 2430108139669253103756

Offset

0,4

Links

Table of n, a(n) for n=0..23.

Formula

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

Prog

(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=2, n, v[i+1]=v[i-1]+sum(j=0, i-1, j*v[j+1]*v[i-j])); v;

Crossrefs

Cf. A075834, A386467.

Cf. A082582.

Sequence in context: A277359 A005362 A059439 * A190123 A006014 A121555

Adjacent sequences: A385284 A385285 A385286 * A385288 A385289 A385290

Keyword

nonn

Author

Seiichi Manyama, Jul 22 2025

Status

approved