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A367715
G.f. A(x) satisfies A(x) = 1 / ((1 - x) * (1 - x * (1 + x + x^2 + x^3) * A(x^4))).
3
1, 2, 4, 8, 16, 33, 68, 140, 288, 594, 1225, 2526, 5208, 10740, 22148, 45673, 94184, 194224, 400524, 825950, 1703249, 3512395, 7243168, 14936668, 30801992, 63519044, 130987274, 270118452, 557031032, 1148694482, 2368807011, 4884890405, 10073490200
OFFSET
0,2
FORMULA
a(n) = 1 + Sum_{k=0..n-1} a(floor(k/4)) * a(n-1-k).
PROG
(PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=1+sum(j=0, i-1, v[j\4+1]*v[i-j])); v;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 28 2023
STATUS
approved