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 A364256 #12 Jul 17 2023 18:00:00
%S A364256 1,1,3,2,1,6,1,4,1,2,1,12,1,2,1,8,1,2,1,4,1,2,1,24,1,2,9,4,1,2,1,16,1,
%T A364256 2,1,4,1,2,1,8,1,2,43,4,5,2,1,48,1,2,1,4,1,18,1,8,1,2,1,4,1,2,3,32,1,
%U A364256 2,1,4,1,2,1,8,1,2,3,4,11,2,1,16,1,2,1,4,1,86,1,8,1,10,7,4,1,2,1,96,1,2,11,4
%N A364256 a(n) = gcd(n, A243071(n)).
%C A364256 Primes p such that a(p) = p are those that occur as factors of (2^A000720(p))-1: 3, 43, 49477. Are there any more of them?
%H A364256 Antti Karttunen, <a href="/A364256/b364256.txt">Table of n, a(n) for n = 1..16384</a>
%H A364256 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%o A364256 (PARI)
%o A364256 A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
%o A364256 A243071(n) = if(n<=2, n-1, if(!(n%2), 2*A243071(n/2), 1+(2*A243071(A064989(n)))));
%o A364256 A364256(n) = gcd(n, A243071(n));
%Y A364256 Cf. A243071.
%Y A364256 Cf. also A364254, A364255.
%K A364256 nonn
%O A364256 1,3
%A A364256 _Antti Karttunen_, Jul 17 2023