A079089 Sum of divisors of (prime(n)+1)*(prime(n+1)+1)/4.

4, 12, 28, 60, 96, 104, 234, 360, 546, 744, 620, 640, 1152, 1488, 1815, 2178, 2304, 1728, 3510, 3458, 3420, 5952, 5760, 4446, 4104, 7056, 8400, 8640, 5760, 10160, 12240, 11232, 13824, 14976, 17360, 11200, 10080, 20160, 21840, 21600, 26208

Offset: 1

Author

Reinhard Zumkeller, Dec 22 2002

Keywords

• nonn

Links

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

Crossrefs

Cf. A000203, A079079, A079088, A079090, A079091.

Programs

Haskell

a079089 = a000203 . a079079  -- Reinhard Zumkeller, Oct 08 2012

Mathematica

a[n_] := DivisorSigma[1, (Prime[n]+1) * (Prime[n+1]+1) / 4]; Array[a, 100] (* Amiram Eldar, Apr 06 2025 *)

PARI

a(n) = sigma((prime(n)+1)*(prime(n+1)+1)/4); \\ Amiram Eldar, Apr 06 2025

Formula

a(n) = A000203(A079079(n)).