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 A305985 #10 Jun 16 2018 18:31:45
%S A305985 1,2,2,3,2,4,5,6,7,8,2,9,10,8,4,11,5,12,5,13,8,14,2,15,16,17,8,18,2,
%T A305985 19,20,18,4,21,8,22,20,21,17,23,2,24,5,25,26,8,5,27,28,29,8,30,2,19,8,
%U A305985 31,21,14,5,32,5,33,26,34,17,35,36,18,4,37,5,32,20,14,26,38,21,39,5,40,41,42,2,43,44,8,14,45,2,46,47,18,44,48,8,49,50,51,12,52,5
%N A305985 Filter sequence combining from all divisors d > 1 of n, the prime signature of 2d+1.
%C A305985 Restricted growth sequence transform of A305984.
%C A305985 For all i, j: a(i) = a(j) => A086668(i) = A086668(j).
%H A305985 Antti Karttunen, <a href="/A305985/b305985.txt">Table of n, a(n) for n = 1..65537</a>
%o A305985 (PARI)
%o A305985 up_to = 65537;
%o A305985 rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
%o A305985 A305984(n) = { my(m=1); fordiv(n, d, if((d>1), m *= prime(A305973(1+d)-1))); (m); }; \\ Needs also code from A305973.
%o A305985 v305985 = rgs_transform(vector(up_to,n,A305984(n)));
%o A305985 A305985(n) = v305985[n];
%Y A305985 Cf. A305810, A305973, A305983, A305984.
%K A305985 nonn
%O A305985 1,2
%A A305985 _Antti Karttunen_, Jun 15 2018