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.

A362641 Product of the smaller primes, p, in the Goldbach partitions of 2n such that p + q = 2n, p <= q, and p,q prime (or 1 if no Goldbach partition of 2n exists).

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%I A362641 #10 Feb 16 2025 08:34:05
%S A362641 1,2,3,3,15,5,21,15,35,21,165,385,273,55,1001,39,2805,7735,133,561,
%T A362641 13585,273,5865,124355,5187,1265,391391,741,27115,19605131,1767,64515,
%U A362641 5766215,217,374187,12212915,313131,170085,142635185,63973,902451,13147103255,223041,101065,818183948197
%N A362641 Product of the smaller primes, p, in the Goldbach partitions of 2n such that p + q = 2n, p <= q, and p,q prime (or 1 if no Goldbach partition of 2n exists).
%H A362641 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GoldbachPartition.html">Goldbach Partition</a>
%H A362641 Wikipedia, <a href="http://en.wikipedia.org/wiki/Goldbach%27s_conjecture">Goldbach's conjecture</a>
%H A362641 <a href="/index/Go#Goldbach">Index entries for sequences related to Goldbach conjecture</a>
%H A362641 <a href="/index/Par#part">Index entries for sequences related to partitions</a>
%F A362641 a(n) = Product_{k=1..n} k^(c(k)*c(2n - k)), where c is the prime characteristic (A010051).
%F A362641 a(n) = Product_{p+q = 2n, p<=q, and p,q prime} p.
%F A362641 a(n) = A337568(n) / A362640(n).
%e A362641 a(10) = 21; 2*10 = 20 has two Goldbach partitions, namely 17+3 and 13+7. The product of the smaller parts of these partitions, is 3*7 = 21.
%t A362641 Table[Product[k^((PrimePi[k] - PrimePi[k - 1]) (PrimePi[2 n - k] - PrimePi[2 n - k - 1])), {k, n}], {n, 40}]
%Y A362641 Cf. A010051, A045917, A337568 (product of all prime parts), A362640 (product of the larger primes q).
%K A362641 nonn,easy
%O A362641 1,2
%A A362641 _Wesley Ivan Hurt_, Apr 28 2023