A114306 - OEIS

A114306

Numbers k such that Fibonacci(k) has more divisors than k does.

9, 12, 15, 16, 18, 19, 20, 21, 24, 25, 27, 28, 30, 31, 32, 33, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 46, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 84, 85, 86, 87, 88, 89, 90, 91

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OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1377 (terms 1..500 from Jinyuan Wang)

EXAMPLE

15 is in the sequence because 610 (= Fibonacci(15)) has more divisors than 15.

MAPLE

with(combinat): with(numtheory): b:=proc(n) if tau(fibonacci(n))>tau(n) then n else fi end: seq(b(n), n=1..100); # Emeric Deutsch, May 13 2006

MATHEMATICA

Select[Range[1, 100], DivisorSigma[0, Fibonacci[#]] > DivisorSigma[0, #] &] (* Vaclav Kotesovec, Feb 13 2019 *)

PROG