A023507 a(n) = sum of distinct prime divisors of prime(n) - 1.

0, 2, 2, 5, 7, 5, 2, 5, 13, 9, 10, 5, 7, 12, 25, 15, 31, 10, 16, 14, 5, 18, 43, 13, 5, 7, 22, 55, 5, 9, 12, 20, 19, 28, 39, 10, 18, 5, 85, 45, 91, 10, 26, 5, 9, 16, 17, 42, 115, 24, 31, 26, 10, 7, 2, 133, 69, 10, 28, 14, 52, 75, 22, 38, 18, 81, 21, 12, 175, 34, 13, 181

Offset

1,2

Links

Table of n, a(n) for n=1..72.

Formula

a(n) = A008472(A006093(n)). - R. J. Mathar, Feb 06 2019

Mathematica

Array[Plus@@First/@FactorInteger[Prime[ # ]-1]&, 5! ] (* Vladimir Joseph Stephan Orlovsky, Feb 28 2010 *)

Crossrefs

Sequence in context: A205674 A021447 A136536 * A095674 A207981 A058123

Adjacent sequences: A023504 A023505 A023506 * A023508 A023509 A023510

Keyword

nonn

Author

Clark Kimberling

Status

approved