A139587 Non-Fibonacci numbers with non-Fibonacci number of divisors.

6, 10, 12, 14, 15, 18, 20, 22, 26, 27, 28, 32, 33, 35, 36, 38, 39, 44, 45, 46, 48, 50, 51, 52, 57, 58, 60, 62, 63, 64, 65, 68, 69, 72, 74, 75, 76, 77, 80, 82, 84, 85, 86, 87, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100, 106, 108, 111

Offset

1,1

Comments

A000005(a(n)) is not a Fibonacci number.

Links

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

Example

6 belongs to the sequence because it is not a Fibonacci number and its number of divisors, 4, is also not a Fibonacci number.

Mathematica

With[{fibs=Fibonacci[Range[12]]}, Select[Range[Max[fibs]], FreeQ[fibs, #] && FreeQ[fibs, DivisorSigma[0, #]]&]] (* Harvey P. Dale, Jun 20 2021 *)

Crossrefs

Non-Fibonacci number: A001690. Cf. A000005, A000045, A139095, A139586, A139588, A139589, A139590.

Sequence in context: A182301 A069059 A273157 * A201463 A119313 A362980

Adjacent sequences: A139584 A139585 A139586 * A139588 A139589 A139590

Keyword

easy,nonn

Author

Omar E. Pol, May 22 2008

Extensions

Example clarified by Harvey P. Dale, Jun 20 2021

Status

approved