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A055696
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Numbers n such that n | Sigma_2(n) + Phi(n)^2.
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0
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1, 2, 6, 182, 330, 850, 2150, 5964, 23028, 85800, 168150, 172250, 179850, 308700, 391300, 484692, 507725, 1098750, 1248148, 1377075, 3105218, 4723500, 9547650, 17353350, 22058792, 37465350, 47094425, 54658450, 110019000, 144820200
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| sigma_2(n) is the sum of the squares of the divisors of n (A001157).
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MATHEMATICA
| Do[If[Mod[DivisorSigma[2, n]+EulerPhi[n]^2, n]==0, Print[n]], {n, 1, 2*10^6}]
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CROSSREFS
| Sequence in context: A137532 A072116 A203430 * A158096 A156517 A091439
Adjacent sequences: A055693 A055694 A055695 * A055697 A055698 A055699
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KEYWORD
| nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 09 2000
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EXTENSIONS
| a(21)-a(30) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 13 2010
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