A050124 a(1)=1; for n > 1, a(n) = floor(a(n-1)/5) if this is not among 0,a(1),...,a(n-1); otherwise a(n) = 2*a(n-1).

1, 2, 4, 8, 16, 3, 6, 12, 24, 48, 9, 18, 36, 7, 14, 28, 5, 10, 20, 40, 80, 160, 32, 64, 128, 25, 50, 100, 200, 400, 800, 1600, 320, 640, 1280, 256, 51, 102, 204, 408, 81, 162, 324, 648, 129, 258, 516, 103, 206, 41, 82, 164, 328, 65

Offset

1,2

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Mathematica

Rest@Nest[Append[#, If[FreeQ[#, r = Quotient[#[[-1]], 5]], r, 2 #[[-1]]]] &, {0, 1}, 53] (* Ivan Neretin, Jul 31 2016 *)

Crossrefs

Cf. A050000 and references therein.

Sequence in context: A218468 A308539 A036122 * A101943 A331440 A247243

Adjacent sequences: A050121 A050122 A050123 * A050125 A050126 A050127

Keyword

nonn

Author

Clark Kimberling

Status

approved