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 A275377 #29 Jul 27 2016 10:20:29 %S A275377 0,1,1,2,1,1,1,5,4,6 %N A275377 Number of odd prime factors (with multiplicity) of generalized Fermat number 3^(2^n) + 1. %H A275377 Arkadiusz Wesolowski, <a href="/A275377/a275377.txt">A 93-digit prime factor of b(9)</a> %F A275377 a(n) = A001222(A059919(n)) - 1 for n > 0. - _Felix Fröhlich_, Jul 25 2016 %e A275377 b(n) = (3^(2^n) + 1)/2. %e A275377 Complete Factorizations %e A275377 b(0) = 2 %e A275377 b(1) = 5 %e A275377 b(2) = 41 %e A275377 b(3) = 17*193 %e A275377 b(4) = 21523361 %e A275377 b(5) = 926510094425921 %e A275377 b(6) = 1716841910146256242328924544641 %e A275377 b(7) = 257*275201*138424618868737*3913786281514524929*P21 %e A275377 b(8) = 12289*8972801*891206124520373602817*P90 %e A275377 b(9) = 134382593*22320686081*12079910333441*100512627347897906177*P93*P101 %o A275377 (PARI) a001222(n) = bigomega(n) %o A275377 a059919(n) = 3^(2^n)+1 %o A275377 a(n) = if(n==0, 0, a001222(a059919(n))-1) \\ _Felix Fröhlich_, Jul 25 2016 %Y A275377 Cf. A059919, A273945. %K A275377 nonn,hard,more %O A275377 0,4 %A A275377 _Arkadiusz Wesolowski_, Jul 25 2016 %E A275377 a(9) was found in 2008 by Tom Womack