A367661 G.f. A(x) satisfies A(x) = 1 / (1 - x - x * A(x^5)).

1, 2, 4, 8, 16, 32, 66, 136, 280, 576, 1184, 2436, 5012, 10312, 21216, 43648, 89800, 184752, 380104, 782016, 1608896, 3310096, 6810096, 14010896, 28825616, 59304992, 122012384, 251024768, 516451136, 1062531712, 2186022176, 4497459138, 9252943048

Offset

0,2

Links

Seiichi Manyama, Table of n, a(n) for n = 0..1000

Formula

a(0) = 1; a(n) = a(n-1) + Sum_{k=0..floor((n-1)/5)} a(k) * a(n-1-5*k).

a(0) = 1, a(1) = 2, a(2) = 4, a(3) = 8, a(4) = 16; a(n) = a(n-5) + Sum_{k=0..n-1} a(floor(k/5)) * a(n-1-k).

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)\5, v[j+1]*v[i-5*j])); v;

Crossrefs

Cf. A349365, A367659, A367660.

Sequence in context: A210542 A141366 A049142 * A303023 A370340 A308032

Adjacent sequences: A367658 A367659 A367660 * A367662 A367663 A367664

Keyword

nonn

Author

Seiichi Manyama, Nov 26 2023

Status

approved