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%I #39 Jul 09 2020 22:39:08
%S 1,4,3,256,8,12,6,64,4294967296,18,12,768,512,24,24
%N a(n) = A225546(sigma(n)).
%C Term a(16) has 309 digits (1025 bits).
%C This is not multiplicative. Even though a(2*3) = a(2)*a(3), a(2*7) = a(2)*a(7), and a(3*5) = a(3)*a(5), we still have a(2*5) = 18 <> a(2)*a(5) = 4*8 = 32.
%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F a(n) = A225546(A000203(n)).
%F A048675(a(n)) = A331750(n).
%t Array[If[# == 1, 1, Times @@ Flatten@ Map[Function[{p, e}, Map[Prime[Log2@ # + 1]^(2^(PrimePi@ p - 1)) &, DeleteCases[NumberExpand[e, 2], 0]]] @@ # &, FactorInteger[#]]] &@ DivisorSigma[1, #] &, 15] (* _Michael De Vlieger_, Jul 08 2020 *)
%o (PARI) A335913(n) = A225546(sigma(n));
%Y Cf. A000203, A048675, A225546, A331733, A331750, A331751.
%Y Cf. also A326042.
%K nonn
%O 1,2
%A _Antti Karttunen_, Jul 07 2020