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A324573 a(1) = 0; for n > 1, a(n) = sigma(A048675(n)).

%I A324573 #9 Mar 08 2019 20:15:04
%S A324573 0,1,3,3,7,4,15,4,7,6,31,7,63,13,12,7,127,6,255,12,18,18,511,6,15,48,
%T A324573 12,18,1023,8,2047,6,39,84,28,12,4095,176,54,8,8191,12,16383,39,15,
%U A324573 258,32767,12,31,13,144,54,65535,8,42,12,252,800,131071,15,262143,1302,28,12,91,20,524287,144,528,14,1048575,8,2097151,2736,18
%N A324573 a(1) = 0; for n > 1, a(n) = sigma(A048675(n)).
%H A324573 Antti Karttunen, <a href="/A324573/b324573.txt">Table of n, a(n) for n = 1..10000</a> (based on Hans Havermann's prime signature data)
%H A324573 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H A324573 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A324573 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A324573 a(1) = 0; for n > 1, a(n) = A000203(A048675(n)).
%o A324573 (PARI)
%o A324573 A048675(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; };
%o A324573 A324573(n) = if(1==n,0,sigma(A048675(n)));
%Y A324573 Cf. A000203, A048675, A324574, A324575.
%Y A324573 Cf. also A277892, A322812, A323243.
%K A324573 nonn
%O A324573 1,3
%A A324573 _Antti Karttunen_, Mar 08 2019