Voozh

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

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OFFSET

1,1

LINKS

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

FORMULA

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

MATHEMATICA

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

DivisorSigma[0, ((#[[1]]+1)(#[[2]]+1))/4]&/@Partition[Prime[Range[80]], 2, 1] (* Harvey P. Dale, Jan 07 2026 *)

PROG

(Haskell)