A367656 G.f. A(x) satisfies A(x) = 1 / (1 - x - x * (1 + x + x^2) * A(x^3)).

1, 2, 5, 13, 35, 94, 252, 678, 1823, 4900, 13176, 35427, 95250, 256105, 688599, 1851450, 4978062, 13384681, 35987808, 96761612, 260166110, 699517054, 1880814358, 5057006914, 13596939262, 36558534049, 98296122593, 264291989596, 710610490247, 1910641595588

Offset

0,2

Links

Table of n, a(n) for n=0..29.

Formula

a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} a(floor(k/3)) * 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, v[j\3+1]*v[i-j])); v;

Crossrefs

Cf. A367655, A367657, A367658.

Cf. A367652, A367659.

Sequence in context: A097919 A160438 A335725 * A240609 A054657 A024576

Adjacent sequences: A367653 A367654 A367655 * A367657 A367658 A367659

Keyword

nonn

Author

Seiichi Manyama, Nov 26 2023

Status

approved