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 A305812 #7 Jun 12 2018 10:16:24
%S A305812 0,1,1,2,1,4,1,6,2,6,1,60,1,4,6,42,1,100,1,198,4,4,1,4620,3,4,10,60,1,
%T A305812 4620,1,546,4,26,6,56100,1,4,4,26334,1,600,1,60,210,10,1,1381380,2,
%U A305812 132,26,60,1,18700,6,4620,4,10,1,66625020,1,4,60,15834,6,1000,1,2418,10,3300,1,334187700,1,4,84,60,4,2200,1,14036022,110,4,1
%N A305812 a(1) = 0; for n > 1, a(n) = Product_{d|n, 1 < d < n} prime(A305788(d)-1).
%H A305812 Antti Karttunen, <a href="/A305812/b305812.txt">Table of n, a(n) for n = 1..8192</a>
%H A305812 <a href="/index/Ge#GF2X">Index entries for sequences operating on GF(2)[X]-polynomials</a>
%F A305812 a(1) = 0; for n > 1, a(n) = Product_{d|n, d<n} A008578(A305788(d)).
%o A305812 (PARI) A305812(n) = if(1==n,0, my(m=1); fordiv(n,d,if((d>1)&&(d<n), m *= prime(A305788(d)-1))); (m)); \\ Needs also code from A305788.
%Y A305812 Cf. A008578, A278233, A305788, A305813 (rgs-transform), A305814.
%Y A305812 Cf. also A305792, A304102.
%K A305812 nonn
%O A305812 1,4
%A A305812 _Antti Karttunen_, Jun 11 2018