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.
%I A325136 #5 Apr 05 2019 05:41:44
%S A325136 1,1,1,1,15,7,35,165,1001,5005,51051,20995,1616615,1716099,5311735,
%T A325136 7436429,3234846615,178752665,955049953,5277907635,19027533679,
%U A325136 176684241305,13829557433055,18960523669087,2180460221945005,8784139751264163,463717784757535,102481630431415235
%N A325136 The product of primes <= 2n that are strongly prime to 2n, bisection of A181836.
%F A325136 a(n) is squarefree.
%p A325136 primes := n -> select(k -> isprime(k), {$1..n}):
%p A325136 strong_prime_to := n -> select(k -> igcd(k,n) = 1, primes(n)) minus numtheory:-divisors(n-1):
%p A325136 A325136 := n -> mul(k, k in strong_prime_to(2*n)):
%p A325136 seq(A325136(n), n=0..27);
%Y A325136 Cf. A181836, A181832, A001783.
%K A325136 nonn
%O A325136 0,5
%A A325136 _Peter Luschny_, Apr 01 2019