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Search: id:A046692
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| 1, -3, -4, 2, -6, 12, -8, 0, 3, 18, -12, -8, -14, 24, 24, 0, -18, -9, -20, -12, 32, 36, -24, 0, 5, 42, 0, -16, -30, -72, -32, 0, 48, 54, 48, 6, -38, 60, 56, 0, -42, -96, -44, -24, -18, 72, -48, 0, 7, -15, 72, -28, -54, 0, 72, 0, 80, 90, -60, 48, -62, 96, -24, 0, 84, -144, -68, -36, 96, -144, -72, 0, -74, 114, -20, -40, 96, -168
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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T. M. Apostol, Introduction to Analytic Number Theory, Springer-Verlag, 1976, page 39.
Feist, Andrew R., Fun With the Sigma-Function, unpub.
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FORMULA
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a(p) = -p-1, a(p^2) = p, a(p^k) = 0 for k > 2.
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EXAMPLE
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a(36) = a(2^2*3^2) = 2*3 = 6
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MAPLE
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t := 1; a := proc(n, t) local t1, d; t1 := 0; for d from 1 to n do if n mod d = 0 then t1 := t1+d^t*mobius(d)*mobius(n/d); fi; od; t1; end;
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PROGRAM
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(PARI) a(n)=if(n<1, 0, direuler(p=2, n, (1-X)*(1-p*X))[n]) (from R. Stephan)
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CROSSREFS
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Cf. A000203.
Sequence in context: A108127 A049277 A143052 this_sequence A166108 A045901 A098003
Adjacent sequences: A046689 A046690 A046691 this_sequence A046693 A046694 A046695
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KEYWORD
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easy,mult,sign,nice
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AUTHOR
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Andrew R. Feist (arf22540(AT)cmsu2.cmsu.edu)
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EXTENSIONS
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Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 13 2006
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