OFFSET
1,3
COMMENTS
EXAMPLE
70 = 2*2*3*5 + 2*5, 72 = 2*2*2*3*3 = 2*2*3*5 + 2*2*3, but 71 is not in the sequence.
MATHEMATICA
S5 = Join[{0}, Select[Range[500], FactorInteger[#][[-1, 1]] <= 5 &]];
Union@Flatten@Outer[Plus, S5, S5]
(* more efficient code by Michael De Vlieger *)
f[n_] := Union@Flatten@Table[2^a*3^b*5^c, {a, 0, Log2[n]}, {b, 0, Log[3, n/2^a]}, {c, 0, Log[5, n/(2^a*3^b)]}]; Block[{nn = 500, s}, s = f[nn]; {0, 1}~Join~
Select[Union@Flatten@Outer[Plus, s, s], # <= nn &]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Carlos Alves, Jan 03 2019
EXTENSIONS
Name edited by Jianing Song, Jun 11 2019
STATUS
approved