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A346073 a(n) = 1 + Sum_{k=0..n-4} a(k) * a(n-k-4). 2
1, 1, 1, 1, 2, 3, 4, 5, 8, 13, 20, 29, 45, 73, 118, 185, 293, 475, 778, 1263, 2047, 3345, 5512, 9085, 14957, 24683, 40918, 67987, 113016, 188053, 313608, 524041, 876657, 1467797, 2460644, 4130893, 6942726, 11678687, 19663068, 33139295, 55904339, 94384167, 159470488 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..42.

FORMULA

G.f. A(x) satisfies: A(x) = 1 / (1 - x) + x^4 * A(x)^2.

MATHEMATICA

a[n_] := a[n] = 1 + Sum[a[k] a[n - k - 4], {k, 0, n - 4}]; Table[a[n], {n, 0, 42}]

nmax = 42; A[_] = 0; Do[A[x_] = 1/(1 - x) + x^4 A[x]^2 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]

CROSSREFS

Cf. A007317, A090344, A216604, A307971, A346074.

Sequence in context: A051706 A292325 A307971 * A211696 A152526 A330706

Adjacent sequences:  A346070 A346071 A346072 * A346074 A346075 A346076

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Jul 04 2021

STATUS

approved

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Last modified December 9 06:07 EST 2021. Contains 349627 sequences. (Running on oeis4.)