A152774 Number of proper divisors of the Fibonacci number A000045(n).

0, 0, 1, 1, 1, 3, 1, 3, 3, 3, 1, 14, 1, 3, 7, 7, 1, 15, 3, 15, 7, 3, 1, 71, 5, 3, 15, 15, 1, 63, 3, 15, 7, 3, 7, 159, 7, 7, 7, 63, 3, 63, 1, 31, 31, 7, 1, 335, 7, 47, 7, 15, 3, 127, 15, 95, 31, 7, 3, 959, 3, 7, 31, 63, 7, 63, 7, 31, 31, 127, 3, 1535, 3, 15, 47, 31, 15, 127, 3

Offset: 1

Author

Omar E. Pol, Jan 17 2009

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1422

Crossrefs

Cf. A000005, A032741, A063375, A074283, A152990.

Programs

Mathematica

a[n_] := DivisorSigma[0, Fibonacci[n]] - 1; Array[a, 100] (* Amiram Eldar, Apr 07 2024 *)

PARI

a(n) = numdiv(fibonacci(n)) - 1; \\ Amiram Eldar, Apr 07 2024

Formula

a(n) = A000005(A000045(n))-1 = A032741(A000045(n)) = A063375(n)-1.