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Products of distinct numbers in A052963.
1

%I #7 Oct 02 2019 16:02:44

%S 2,5,10,14,28,40,70,80,115,140,200,230,331,400,560,575,662,953,1120,

%T 1150,1610,1655,1906,2744,2800,3220,3310,4600,4634,4765,5488,5600,

%U 7901,8050,9200,9268,9530,13240,13342,13720,15802,16100,22750,23000,23170,26480

%N Products of distinct numbers in A052963.

%H Clark Kimberling, <a href="/A274453/b274453.txt">Table of n, a(n) for n = 1..10000</a>

%e The numbers in A274453 are 1, 2, 5, 14, 40, 115, 331,..., so that the sequence of all products of distinct members, in increasing order, is (2, 5, 10, 14, 28, 40, 70, 80,...).

%t r[1] := 1; r[2] := 1; r[3] = 1; r[n_] := r[n] = 3 r[n - 1] - r[n - 3]

%t s = {1}; z = 30; f = Map[r, Range[z]]; Take[f, 20] (* A052963 *)

%t Do[s = Union[s, Select[s*f[[i]], # <= f[[z]] &]], {i, z}];

%t Take[s, 2 z] (* A274453 *)

%Y Cf. A160009, A274280, A274432, A274452.

%K nonn,easy

%O 1,1

%A _Clark Kimberling_, Jun 23 2016