A274454 Products of distinct numbers in the Pell sequence (A000129).

2, 5, 10, 12, 24, 29, 58, 60, 70, 120, 140, 145, 169, 290, 338, 348, 350, 408, 696, 700, 816, 840, 845, 985, 1680, 1690, 1740, 1970, 2028, 2030, 2040, 2378, 3480, 4056, 4060, 4080, 4200, 4756, 4896, 4901, 4925, 5741, 8400, 9792, 9802, 9850, 10140, 10150

Offset

1,1

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Example

The numbers in A274454 are 1, 2, 5, 12, 29, 70, 169, 408,..., so that the sequence of all products of distinct members, in increasing order, is (2, 5, 10, 12, 24, 29, 58, 60,...).

Mathematica

r[1] = 1; r[2] = 2; r[n_] := r[n] = 2 r[n - 1] + r[n - 2]
s = {1}; z = 30; f = Map[r, Range[z]]; Take[f, 20] (* A000129 *)
Do[s = Union[s, Select[s*f[[i]], # <= f[[z]] &]], {i, z}];
Take[s, 2 z]  (* A274454 *)

Crossrefs

Cf. A160009, A274280.

Sequence in context: A351062 A182656 A090050 * A192539 A046462 A188025

Adjacent sequences: A274451 A274452 A274453 * A274455 A274456 A274457

Keyword

nonn,easy

Author

Clark Kimberling, Jun 23 2016

Status

approved