A139588 - OEIS

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A139588

Nonprime numbers with Fibonacci number of divisors.

1, 4, 9, 16, 24, 25, 30, 40, 42, 49, 54, 56, 66, 70, 78, 81, 88, 102, 104, 105, 110, 114, 121, 128, 130, 135, 136, 138, 152, 154, 165, 169, 170, 174, 182, 184, 186, 189, 190, 195, 222, 230, 231, 232, 238, 246, 248, 250, 255, 258, 266, 273, 282, 285, 286, 289

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

A000005(a(n)) is a Fibonacci number.

The union of {1}, A001248, A030514, A030626, A030631, A137484, etc. [From R. J. Mathar, Oct 26 2009]

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

A123193 \ A000040. [From R. J. Mathar, Oct 23 2009]

MATHEMATICA

Module[{fibs=Fibonacci[Range[20]]}, Select[Range[300], !PrimeQ[#]&&MemberQ[ fibs, DivisorSigma[0, #]]&]] (* Harvey P. Dale, Jan 20 2023 *)