A079088 Number of divisors of (prime(n)+1)*(prime(n+1)+1)/4.

2, 4, 6, 8, 8, 6, 12, 16, 18, 20, 10, 8, 16, 20, 20, 20, 16, 8, 24, 18, 16, 40, 32, 18, 12, 24, 32, 32, 16, 28, 32, 24, 32, 32, 36, 12, 8, 32, 36, 32, 48, 48, 24, 12, 54, 24, 24, 48, 32, 24, 64, 48, 36, 32, 36, 60, 64, 16, 8, 16, 24, 32, 64, 24, 8, 16, 12, 24, 48, 24, 48, 72, 32, 32

Offset: 1

Author

Reinhard Zumkeller, Dec 22 2002

Keywords

• nonn

Links

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

Crossrefs

Cf. A000005, A079079, A079085, A079086.

Programs

Haskell

a079088 = a000005 . a079079  -- Reinhard Zumkeller, Oct 08 2012

Mathematica

a[n_] := DivisorSigma[0, (Prime[n]+1) * (Prime[n+1]+1) / 4]; Array[a, 100] (* Amiram Eldar, Apr 06 2025 *)

PARI

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

Formula

a(n) = A000005(A079079(n)).