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 A339898 #9 Dec 28 2020 09:51:38
%S A339898 0,0,0,0,0,2,1,2,0,2,4,4,1,5,9,14,0,2,1,2,0,2,4,5,7,8,9,14,10,32,9,29,
%T A339898 0,0,0,0,1,2,0,2,1,0,4,4,3,11,4,14,1,2,0,2,7,5,3,2,0,2,4,14,6,20,34,
%U A339898 14,0,2,4,5,24,20,16,23,28,41,9,29,112,68,24,74,3,11,19,5,27,2,58,14,16,50,84,119,388,356
%N A339898 a(n) = A019565(2n)-1 mod A000265(phi(A019565(2n))).
%H A339898 Antti Karttunen, <a href="/A339898/b339898.txt">Table of n, a(n) for n = 0..8192</a>
%H A339898 Antti Karttunen, <a href="/A339898/a339898.txt">Data supplement: n, a(n) computed for n = 0..65537</a>
%F A339898 a(n) = A339809(2*n) modulo A339971(n), where A339971(n) = A053575(A019565(2n)).
%o A339898 (PARI)
%o A339898 A000265(n) = (n>>valuation(n,2));
%o A339898 A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); };
%o A339898 A339898(n) = { my(x=A019565(2*n)); ((x-1)%A000265(eulerphi(x))); };
%Y A339898 Cf. A053575, A019565, A339809, A339821, A339971, A339899, A339901.
%Y A339898 Cf. A339973 (positions of zeros).
%K A339898 nonn
%O A339898 0,6
%A A339898 _Antti Karttunen_, Dec 28 2020