A079085 - OEIS

A079085

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

1, 2, 2, 2, 3, 2, 3, 3, 3, 3, 2, 3, 4, 3, 2, 3, 4, 3, 3, 3, 3, 4, 4, 3, 3, 4, 3, 4, 4, 3, 3, 4, 5, 4, 4, 3, 3, 4, 4, 4, 5, 4, 3, 3, 4, 3, 3, 4, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 4, 4, 4, 5, 4, 3, 4, 3, 4, 5, 4, 4, 4, 4, 5, 4, 4, 4, 3, 4, 5, 5, 3, 4, 5, 5, 4, 3, 4, 5, 4, 4, 4, 4, 4, 4, 5, 4, 4, 3, 3, 4, 4, 5, 6, 4

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OFFSET

1,2

LINKS

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

FORMULA

a(n) = A001221(A079079(n)).

MATHEMATICA

Table[PrimeNu[(Prime[n] + 1)*(Prime[n + 1] + 1)/4], {n, 1, 50}] (* G. C. Greubel, Apr 25 2017 *)

PROG

(Haskell)

a079085 = a001221 . a079079 -- Reinhard Zumkeller, Oct 08 2012