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Natural numbers with number of divisors not equal to a Fibonacci number.
5

%I #7 Mar 18 2023 13:51:31

%S 6,8,10,12,14,15,18,20,21,22,26,27,28,32,33,34,35,36,38,39,44,45,46,

%T 48,50,51,52,55,57,58,60,62,63,64,65,68,69,72,74,75,76,77,80,82,84,85,

%U 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

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

%C 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]

%H T. D. Noe, <a href="/A123240/b123240.txt">Table of n, a(n) for n=1..10000</a>

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

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

%K easy,nonn

%O 1,1

%A _Giovanni Teofilatto_, Oct 07 2006