A322821 - OEIS

%I #8 Dec 28 2018 10:02:51

%S 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 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 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 a(1) = 0; for n > 1, a(n) = A000265(A048675(n)).

%H Antti Karttunen, <a href="/A322821/b322821.txt">Table of n, a(n) for n = 1..4096</a>

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%F a(1) = 0; for n > 1, a(n) = A000265(A048675(n)).

%o (PARI)

%o A000265(n) = (n>>valuation(n, 2));

%o A048675(n) = my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; \\ From A048675

%o A322821(n) = if(1==n,0,A000265(A048675(n)));

%Y Cf. A000265, A048675, A322815, A322816.

%K nonn

%O 1,6

%A _Antti Karttunen_, Dec 27 2018