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 A275378 #22 Aug 07 2019 07:42:13
%S A275378 1,1,1,2,2,3,3,3,5
%N A275378 Number of odd prime factors (with multiplicity) of generalized Fermat number 5^(2^n) + 1.
%H A275378 factordb.com, <a href="http://factordb.com/index.php?query=5%5E%282%5En%29%2B1">Status of 5^(2^n)+1</a>.
%F A275378 a(n) = A001222(A199591(n)) - 1. - _Felix Fröhlich_, Jul 25 2016
%e A275378 b(n) = (5^(2^n) + 1)/2.
%e A275378 Complete Factorizations
%e A275378 b(0) = 3
%e A275378 b(1) = 13
%e A275378 b(2) = 313
%e A275378 b(3) = 17*11489
%e A275378 b(4) = 2593*29423041
%e A275378 b(5) = 641*75068993*241931001601
%e A275378 b(6) = 769*3666499598977*96132956782643741951225664001
%e A275378 b(7) = 257*23653200983830003298459393*P62
%e A275378 b(8) = 1655809*101199664791578113*4563566430220614493697*
%e A275378 12025702000065183805751513732616276516181800961*P88
%t A275378 Table[PrimeOmega[(5^(2^n) + 1)/2], {n, 0, 6}] (* _Michael De Vlieger_, Jul 26 2016 *)
%o A275378 (PARI) a(n) = bigomega(factor((5^(2^n)+1)/2))
%Y A275378 Cf. A199591, A273946.
%K A275378 nonn,hard,more
%O A275378 0,4
%A A275378 _Arkadiusz Wesolowski_, Jul 25 2016