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

1,6

Links

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

Formula

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

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A023136 A337333 A348665 * A275820 A210146 A354198

Adjacent sequences: A152771 A152772 A152773 * A152775 A152776 A152777

Keyword

nonn

Author

Omar E. Pol, Jan 17 2009

Status

approved