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 A260300 #9 Nov 10 2015 08:58:49 %S A260300 2,4,6,2,10,12,2,16,18,2,22,4,2,28,30,2,2,36,2,40,42,2,46,6,2,52,2,2, %T A260300 58,60,2,4,66,2,70,72,2,2,78,2,82,4,2,88,6,2,2,96,2,100,102,2,106,108, %U A260300 2,112,2,2,2,10,2,4,126,2,130,6,2,136,138,2,2,4,2,148,150 %N A260300 Bisection of A258409: a(n) = A258409(2n+1). %o A260300 (PARI) a(n) = gcd(apply(x->x-1, divisors(2*n+1))); %Y A260300 Cf. A258409. %K A260300 nonn %O A260300 1,1 %A A260300 _Michel Marcus_, Nov 10 2015