cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A254232 Product of Perrin numbers A001608(2) * ... * A001608(n).

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%I A254232 #20 Jan 07 2022 01:08:31
%S A254232 2,6,12,60,300,2100,21000,252000,4284000,94248000,2733192000,
%T A254232 106594488000,5436318888000,369669684384000,33270271594560000,
%U A254232 3959162319752640000,625547646520917120000,130739458122871678080000,36214829900035454828160000
%N A254232 Product of Perrin numbers A001608(2) * ... * A001608(n).
%H A254232 Chai Wah Wu, <a href="/A254232/b254232.txt">Table of n, a(n) for n = 2..127</a>
%F A254232 a(n) ~ c * r^(n*(n+1)/2), where r = A060006 = 1.324717957244746025960908854478... is the root of the equation r^3 = r + 1, c = 0.81845731383668335747954234022593868885066763327809025622515304041339344876... .
%t A254232 Table[Product[SeriesCoefficient[(3-x^2)/(1-x^2-x^3),{x,0,k}],{k,2,n}], {n,2,20}]
%o A254232 (Python)
%o A254232 A254232_list, a, b, c, d = [2], 3, 0, 2, 2
%o A254232 for _ in range(200):
%o A254232     a, b, c = b, c, a+b
%o A254232     d *= c
%o A254232     A254232_list.append(d) # _Chai Wah Wu_, Jan 28 2015
%Y A254232 Cf. A001608, A003266, A060006, A126772, A135407, A254231.
%K A254232 nonn
%O A254232 2,1
%A A254232 _Vaclav Kotesovec_, Jan 27 2015