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A274454
Products of distinct numbers in the Pell sequence (A000129).
1
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
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
Sequence in context: A351062 A182656 A090050 * A192539 A046462 A188025
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 23 2016
STATUS
approved