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A309530 Number of power-of-two-divisors of sum of divisors of sum of divisors of powers of two: a(n) = A001511(A051027(A000079(n))). 1

%I

%S 1,3,4,4,6,4,8,5,5,10,5,6,14,12,12,6,18,10,20,11,9,9,6,8,8,18,6,15,7,

%T 16,32,7,11,22,17,14,7,24,22,13,5,13,11,12,20,10,7,11,9,16,33,22,6,10,

%U 15,17,28,12,6,20,62,36,12,9,24,16,5,26,12,26,10,18,6,12,16,28,19,26

%N Number of power-of-two-divisors of sum of divisors of sum of divisors of powers of two: a(n) = A001511(A051027(A000079(n))).

%H Juri-Stepan Gerasimov,<a href="http://list.seqfan.eu/pipermail/seqfan/2019-August/018893.html">x = A001511(A051027(A000079(x)))</a>,SeqFan list, Aug 19 2019.

%F a(n) = A001511(A051027(A000079(n))).

%e a(0) = A001511(A051027(A000079(0))) = A001511(A051027(A000079(2^0))) = A001511(A051027(1)) = A001511(1) = 1.

%o (MAGMA) [Valuation(2*SumOfDivisors(SumOfDivisors(2^n)),2): n in [0..89]];

%o (PARI) a(n) = valuation(2*sigma(sigma(2^n)), 2); \\ _Michel Marcus_, Aug 06 2019

%Y Cf. A000043 (numbers m such that m - 1 divides a(m - 1) - 2), A000079, A001511, A051027, A090748.

%K nonn

%O 0,2

%A _Juri-Stepan Gerasimov_, Aug 06 2019

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Last modified September 27 14:52 EDT 2020. Contains 337383 sequences. (Running on oeis4.)