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A055696 Numbers n such that n | Sigma_2(n) + Phi(n)^2. +0
1
1, 2, 6, 182, 330, 850, 2150, 5964, 23028, 85800, 168150, 172250, 179850, 308700, 391300, 484692, 507725, 1098750, 1248148, 1377075 (list; graph; listen)
OFFSET

1,2

COMMENT

sigma_2(n) is the sum of the squares of the divisors of n (A001157).

MATHEMATICA

Do[If[Mod[DivisorSigma[2, n]+EulerPhi[n]^2, n]==0, Print[n]], {n, 1, 2*10^6}]

CROSSREFS

Sequence in context: A135937 A137532 A072116 this_sequence A158096 A156517 A091439

Adjacent sequences: A055693 A055694 A055695 this_sequence A055697 A055698 A055699

KEYWORD

nonn

AUTHOR

Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 09 2000

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.


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