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A346074 a(n) = 1 + Sum_{k=0..n-5} a(k) * a(n-k-5). 2

%I

%S 1,1,1,1,1,2,3,4,5,6,9,14,21,30,41,59,89,136,205,301,443,664,1011,

%T 1545,2341,3530,5341,8143,12487,19148,29299,44817,68721,105742,163025,

%U 251392,387595,597988,924047,1430167,2215595,3433788,5323915,8260652,12829849

%N a(n) = 1 + Sum_{k=0..n-5} a(k) * a(n-k-5).

%F G.f. A(x) satisfies: A(x) = 1 / (1 - x) + x^5 * A(x)^2.

%t a[n_] := a[n] = 1 + Sum[a[k] a[n - k - 5], {k, 0, n - 5}]; Table[a[n], {n, 0, 44}]

%t nmax = 44; A[_] = 0; Do[A[x_] = 1/(1 - x) + x^5 A[x]^2 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]

%Y Cf. A007317, A090344, A216604, A307972, A346073.

%K nonn

%O 0,6

%A _Ilya Gutkovskiy_, Jul 04 2021

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Last modified November 28 13:39 EST 2021. Contains 349412 sequences. (Running on oeis4.)