A123240 Natural numbers with number of divisors not equal to a Fibonacci number.

6, 8, 10, 12, 14, 15, 18, 20, 21, 22, 26, 27, 28, 32, 33, 34, 35, 36, 38, 39, 44, 45, 46, 48, 50, 51, 52, 55, 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, 112, 115, 116, 117, 118, 119, 120, 122, 123, 124, 125, 126, 129, 132, 133, 134, 140, 141, 142, 143, 144, 145, 146, 147, 148, 150, 153, 155, 156, 158, 159, 160, 161, 162, 164, 166, 168, 171, 172, 175, 176, 177, 178, 180, 183, 185, 187, 188, 192, 194, 196, 198, 200, 201, 202, 203, 204

Offset

1,1

Comments

No prime or square of a prime or square of a prime's square is included in this sequence. [From Avik Roy (avik_3.1416(AT)yahoo.co.in), Jan 23 2009]

Links

T. D. Noe, Table of n, a(n) for n=1..10000

Mathematica

If[MemberQ[Fibonacci[Range[20]], DivisorSigma[0, #]], Nothing, #]&/@Range[250] (* Harvey P. Dale, Mar 18 2023 *)

Crossrefs

Complement of A123193. Different from A000379 (e.g. contains 180).

Sequence in context: A139118 A089229 A345945 * A131181 A064176 A000379

Adjacent sequences: A123237 A123238 A123239 * A123241 A123242 A123243

Keyword

easy,nonn

Author

Giovanni Teofilatto, Oct 07 2006

Status

approved