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 A203692 v(n+1)/v(n), where v=A203691. 2

%I #10 Nov 21 2023 07:47:58

%S 13,2709,3024084,11210422275,105517529064567,2124369691794486864,

%T 81235403341710637909248,5408406067938289043927788125,

%U 586601588860841615474452259390625,98362502736855752633918233259787105024

%N v(n+1)/v(n), where v=A203691.

%C See A093883 for a discussion and guide to related sequences.

%F a(n) ~ 3^(3*n/2 + 7/4) * exp(sqrt(3)*Pi*(2*n+3)/4 - 4*n) * n^(4*n) / 2^(2*n). - _Vaclav Kotesovec_, Nov 21 2023

%t f[j_] := j (j + 1)/2; z = 11;

%t u[n_] := Product[f[j]^2 + f[j] f[k] + f[k]^2,

%t {j, 1, k - 1}]

%t v[n_] := Product[u[n], {k, 2, n}]

%t Table[v[n], {n, 1, z}] (* A203691 *)

%t Table[v[n + 1]/v[n], {n, 1, z}] (* A203692 *)

%t Table[Product[k^2*(k + 1)^2/4 + k*(k + 1)*(n + 1)*(n + 2)/4 + (n + 1)^2*(n + 2)^2/4, {k, 1, n}], {n, 1, 10}] (* _Vaclav Kotesovec_, Nov 21 2023 *)

%K nonn

%O 1,1

%A _Clark Kimberling_, Jan 04 2012

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Last modified May 21 05:34 EDT 2024. Contains 372728 sequences. (Running on oeis4.)