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 A274452 Products of distinct Narayana's cow numbers (A000930). 2
 2, 3, 4, 6, 8, 9, 12, 13, 18, 19, 24, 26, 27, 28, 36, 38, 39, 41, 48, 52, 54, 56, 57, 60, 72, 76, 78, 82, 84, 88, 104, 108, 112, 114, 117, 120, 123, 129, 144, 152, 156, 162, 164, 168, 171, 176, 180, 189, 216, 224, 228, 234, 240, 246, 247, 252, 258, 264, 277 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Clark Kimberling, Table of n, a(n) for n = 1..10000 EXAMPLE The Narayana's cow numbers numbers are 1, 2, 3, 4, 6, 9, 13, 19, 28, ..., so that the sequence of all products of distinct members, in increasing order, is (2, 3, 4, 6, 8, 9, 12, 13, 18, 19, 24, ...). MATHEMATICA r[1] := 1; r[2] := 1; r[3] = 1; r[n_] := r[n] = r[n - 1] + r[n - 3] s = {1}; z = 60; f = Map[r, Range[z]]; Take[f, 20] (*A000930*) Do[s = Union[s, Select[s*f[[i]], # <= f[[z]] &]], {i, z}]; Take[s, 2 z] (* A274452 *) CROSSREFS Cf. A160009, A274280, A274432. Sequence in context: A278580 A028929 A308299 * A018731 A232966 A331728 Adjacent sequences:  A274449 A274450 A274451 * A274453 A274454 A274455 KEYWORD nonn,easy AUTHOR Clark Kimberling, Jun 23 2016 STATUS approved

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Last modified September 23 00:32 EDT 2021. Contains 347609 sequences. (Running on oeis4.)