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

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 *)

Crossrefs

Cf. A000005, A000045, A018252, A123193, A139589, A139590.

Sequence in context: A008030 A168086 A176238 * A320894 A122986 A066427

Adjacent sequences: A139585 A139586 A139587 * A139589 A139590 A139591

Keyword

easy,nonn

Author

Omar E. Pol, May 09 2008

Extensions

More terms from R. J. Mathar, Oct 23 2009

Status

approved