A272916 Numbers that are a product of two Fibonacci (A000045) numbers or a product of two Lucas (A000032) numbers.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 18, 21, 24, 25, 26, 28, 29, 33, 34, 39, 40, 42, 44, 47, 49, 54, 55, 63, 64, 65, 68, 72, 76, 77, 87, 89, 102, 104, 105, 110, 116, 121, 123, 126, 141, 144, 165, 168, 169, 170, 178, 188, 198, 199, 203, 228, 233

Offset: 1

Author

Clark Kimberling, May 10 2016

Keywords

• nonn
• easy

Comments

Conjecture: if c and d are consecutive terms, then d - c is a term.

Examples

			Equals union(A049997, A272909), in increasing order.
		

Links

• Clark Kimberling, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000032, A000045, A049997, A272909, A272917 (difference sequence).

Programs

Mathematica

z = 400; u2 = Sort[Flatten[Table[Fibonacci[i + 1] * Fibonacci[j + 1], {i, 1, z}, {j, i, z}]]];
v2 = Sort[Flatten[Table[LucasL[i]*LucasL[j], {i, 1, z}, {j, i, z}]]];
u = Take[Union[u2, v2], 200] (* A272916 *)
d = Take[Differences[u], 200]  (* A272917 *)