A119885 Natural numbers with number of divisors equal to a Lucas number.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 25, 26, 27, 29, 31, 33, 34, 35, 37, 38, 39, 41, 43, 46, 47, 49, 51, 53, 55, 57, 58, 59, 61, 62, 64, 65, 67, 69, 71, 73, 74, 77, 79, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 101, 103

Offset: 1

Author

Giovanni Teofilatto, Aug 01 2006

Keywords

• easy
• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

For natural numbers with number of divisors equal to a Fibonacci number, see A123193. [corrected by Matthew Vandermast, Oct 29 2008]

Cf. A000032.

Programs

Mathematica

lim = 250; t = LucasL /@ Range[0, lim]; Select[Range@ lim, MemberQ[t, DivisorSigma[0, #]] &]  (* Amiram Eldar, Sep 05 2019 after Michael De Vlieger at A123193 *)