A200995 Numbers not expressible as a product of Lucas numbers.

5, 10, 13, 15, 17, 19, 20, 23, 25, 26, 30, 31, 34, 35, 37, 38, 39, 40, 41, 43, 45, 46, 50, 51, 52, 53, 55, 57, 59, 60, 61, 62, 65, 67, 68, 69, 70, 71, 73, 74, 75, 78, 79, 80, 82, 83, 85, 86, 89, 90, 91, 92, 93, 95, 97, 100, 101, 102, 103, 104, 105, 106, 107, 109

Offset: 1

Author

Arkadiusz Wesolowski, Jan 07 2013

Keywords

• nonn

Comments

a(n+1) - a(n) <= 5 for all n.

Examples

			65 = 5*13 is not the product of Lucas numbers, so 65 is in the sequence.
		

Links

• Arkadiusz Wesolowski, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Lucas Number
• Index entries for Lucas sequences

Crossrefs

Cf. A000032. Complement of A200381.

Programs

Mathematica

listMultiply[lst_] := Take[Union@Flatten@Table[lst[[i]]*lst[[j]], {i, Length[lst]}, {j, i}], 46]; A200381 = Nest[listMultiply, LucasL@Range[0, 9], 3]; Complement[Range@Last[A200381], A200381]