A131096 3-smooth numbers in ternary representation.

1, 2, 10, 11, 20, 22, 100, 110, 121, 200, 220, 1000, 1012, 1100, 1210, 2000, 2101, 2200, 10000, 10120, 11000, 11202, 12100, 20000, 21010, 22000, 100000, 100111, 101200, 110000, 112020, 121000, 200000, 200222, 210100, 220000, 1000000, 1001110

Offset: 1

Author

Reinhard Zumkeller, Jun 14 2007

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Ternary.

Crossrefs

Cf. A003586, A007089.

Programs

Mathematica

smooth3Q[n_] := FactorInteger[n][[-1, 1]] <= 3;
FromDigits /@ (IntegerDigits[#, 3]& /@ Select[Range[10000], smooth3Q]) (* Jean-François Alcover, Oct 17 2021 *)

Formula

a(n) = A007089(A003586(n)).

Extensions

Offset changed to 1 by Joerg Arndt, Oct 17 2021