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A034713
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Dirichlet convolution of powers of 2 (2,4,8,...) with themselves.
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0
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4, 16, 32, 80, 128, 320, 512, 1152, 2112, 4352, 8192, 17152, 32768, 66560, 131584, 264448, 524288, 1053696, 2097152, 4203520, 8390656, 16793600, 33554432, 67147776, 134218752, 268500992, 536879104, 1073876992, 2147483648
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..29.
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FORMULA
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a(n) = 4 * A034733(n).
G.f.: Sum_{k>=1} 2^(k+1)*x^k/(1 - 2*x^k). - Ilya Gutkovskiy, Sep 10 2019
a(n) ~ 2^(n+2). - Vaclav Kotesovec, Sep 11 2019
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MATHEMATICA
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Table[Sum[2^(d + n/d), {d, Divisors[n]}], {n, 1, 30}] (* Vaclav Kotesovec, Sep 11 2019 *)
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PROG
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(PARI) a(n) = if(n==0, 1, sumdiv(n, d, 2^d * 2^(n/d) )); \\ Joerg Arndt, Apr 14 2013
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CROSSREFS
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Cf. A000079, A034733.
Sequence in context: A326873 A126032 A296819 * A101653 A043100 A329853
Adjacent sequences: A034710 A034711 A034712 * A034714 A034715 A034716
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KEYWORD
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nonn
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AUTHOR
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Erich Friedman
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STATUS
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approved
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