A234861 - OEIS

A234861

Sum of the distinct prime divisors of n^3 - 1.

0, 7, 15, 10, 33, 48, 24, 80, 22, 40, 33, 168, 66, 224, 250, 28, 309, 24, 132, 440, 470, 23, 99, 624, 43, 61, 772, 274, 89, 55, 341, 189, 1125, 411, 129, 86, 79, 1520, 251, 563, 1730, 193, 643, 333, 141, 118, 123, 241, 67, 2558, 393, 939, 431, 3024, 97, 150

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OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

EXAMPLE

a(3) = 15 because 3^3-1 = 26 and the sum of the 2 distinct prime divisors {2, 13} is 15.

MATHEMATICA

Table[Total[Transpose[FactorInteger[n^3 - 1]][[1]]], {n, 50}]

CROSSREFS

Cf. A062835.

Sequence in context: A289966 A290621 A290629 * A076401 A180114 A204740

Adjacent sequences: A234858 A234859 A234860 * A234862 A234863 A234864

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Jan 01 2014

STATUS

approved