0,2

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

a(3) = 9 because 3^3+1 = 28 and the sum of the 2 distinct prime divisors {2, 7} is 9.

Join[{0}, Table[Total[Transpose[FactorInteger[n^3 + 1]][[1]]], {n, 60}]]

Cf. A193462.

Sequence in context: A302164 A295965 A034467 * A065965 A296052 A108827

Adjacent sequences: A234643 A234644 A234645 * A234647 A234648 A234649

nonn

Vincenzo Librandi, Jan 01 2014

approved