A220586 Numbers n such that (the sum of the divisors of n) plus (the sum of the squares of the divisors of n) plus (the sum of the cubes of the divisors of n) is a prime number.

1, 2, 4, 18, 25, 100, 484, 1089, 1156, 2809, 11449, 42025, 52900, 63001, 119716, 120409, 196249, 218089, 220900, 280900, 310249, 407044, 491401, 594441, 632025, 651249, 697225, 1012036, 1062961, 1134225, 1216609, 1240996, 1408969, 1643524, 1646089, 1692601

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..500

Mathematica

Select[Range[5000000], PrimeQ[DivisorSigma[1, #] + DivisorSigma[2, #] + DivisorSigma[3, #]]&]

Crossrefs

Cf. A000040, A000203, A001157, A001158.

Sequence in context: A076692 A350629 A357998 * A054300 A303360 A303442

Adjacent sequences: A220583 A220584 A220585 * A220587 A220588 A220589

Keyword

nonn

Author

Harvey P. Dale, Dec 16 2012

Extensions

a(1) = 1 added by Amiram Eldar, Aug 07 2019

Status

approved