A079090 Sum of distinct prime factors of (prime(n)+1)*(prime(n+1)+1)/4.

3, 5, 5, 5, 12, 10, 10, 10, 10, 10, 21, 29, 23, 16, 5, 10, 41, 50, 22, 42, 44, 17, 17, 15, 27, 35, 18, 21, 38, 24, 16, 39, 40, 17, 29, 100, 122, 53, 41, 39, 30, 25, 102, 111, 21, 60, 62, 31, 52, 44, 23, 21, 23, 55, 59, 21, 27, 158, 189, 123, 83, 23, 36, 175, 213, 141, 98, 47

Offset: 1

Author

Reinhard Zumkeller, Dec 22 2002

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A008472, A079079, A079085, A079089, A079091.

Programs

Haskell

a079090 = a008472 . a079079  -- Reinhard Zumkeller, Oct 09 2012

Mathematica

Total[Transpose[FactorInteger[((#[[1]]+1)(#[[2]]+1))/4]][[1]]]&/@ Partition[Prime[Range[70]],2,1] (* Harvey P. Dale, Apr 24 2015 *)

PARI

a(n) = vecsum(factor((prime(n)+1)*(prime(n+1)+1)/4)[, 1]); \\ Amiram Eldar, Apr 07 2025

Formula

a(n) = A008472(A079079(n)).