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A086455 Sum of divisors of prime powers: sigma(p^e). 4
1, 3, 4, 7, 6, 8, 15, 13, 12, 14, 31, 18, 20, 24, 31, 40, 30, 32, 63, 38, 42, 44, 48, 57, 54, 60, 62, 127, 68, 72, 74, 80, 121, 84, 90, 98, 102, 104, 108, 110, 114, 133, 156, 128, 255, 132, 138, 140, 150, 152, 158, 164, 168, 183, 174, 180, 182, 192, 194, 198 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = A000203(A000961(n)).

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Prime Power.

Eric Weisstein's World of Mathematics, Divisor Function

FORMULA

a(p^e) = (p^(e+1)-1)/(p-1): a(n)=(A025473(n)^(A025474(n)+1)-1)/(A025473(n)-1).

MAPLE

A086455 := proc(n)

    numtheory[sigma](A000961(n)) ;

end proc: # R. J. Mathar, Jun 04 2016

MATHEMATICA

DivisorSigma[1, #]& /@ Join[{1}, Select[Range[2, 200], PrimePowerQ]] (* Jean-Fran├žois Alcover, Feb 10 2018 *)

CROSSREFS

Cf. A086454.

Sequence in context: A183107 A132009 A295565 * A204823 A211657 A215430

Adjacent sequences:  A086452 A086453 A086454 * A086456 A086457 A086458

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 20 2003

STATUS

approved

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Last modified October 18 14:44 EDT 2019. Contains 328161 sequences. (Running on oeis4.)