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

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

(PARI) isok(n) = numdiv(fibonacci(n)) > numdiv(n); \\ Michel Marcus, Feb 13 2019

Crossrefs

Cf. A000005, A000045, A063375.

Sequence in context: A044859 A336754 A336756 * A009188 A138299 A050435

Adjacent sequences: A114303 A114304 A114305 * A114307 A114308 A114309

Keyword

nonn

Author

Shyam Sunder Gupta, Feb 05 2006

Status

approved