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 A322821 #8 Dec 28 2018 10:02:51 %S A322821 0,1,1,1,1,3,1,3,1,5,1,1,1,9,3,1,1,5,1,3,5,17,1,5,1,33,3,5,1,7,1,5,9, %T A322821 65,3,3,1,129,17,7,1,11,1,9,1,257,1,3,1,9,33,17,1,7,5,11,65,513,1,1,1, %U A322821 1025,3,3,9,19,1,33,129,13,1,7,1,2049,5,65,3,35,1,1,1,4097,1,3,17,8193,257,19,1,9,5,129,513,16385,33,7,1 %N A322821 a(1) = 0; for n > 1, a(n) = A000265(A048675(n)). %H A322821 Antti Karttunen, <a href="/A322821/b322821.txt">Table of n, a(n) for n = 1..4096</a> %H A322821 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a> %F A322821 a(1) = 0; for n > 1, a(n) = A000265(A048675(n)). %o A322821 (PARI) %o A322821 A000265(n) = (n>>valuation(n, 2)); %o A322821 A048675(n) = my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; \\ From A048675 %o A322821 A322821(n) = if(1==n,0,A000265(A048675(n))); %Y A322821 Cf. A000265, A048675, A322815, A322816. %K A322821 nonn %O A322821 1,6 %A A322821 _Antti Karttunen_, Dec 27 2018