A050004 a(n) = floor(a(n-1)/2) if this is not among 0, a(1), ..., a(n-2); otherwise a(n) = 5*a(n-1).

1, 5, 2, 10, 50, 25, 12, 6, 3, 15, 7, 35, 17, 8, 4, 20, 100, 500, 250, 125, 62, 31, 155, 77, 38, 19, 9, 45, 22, 11, 55, 27, 13, 65, 32, 16, 80, 40, 200, 1000, 5000, 2500, 1250, 625, 312, 156, 78, 39, 195, 97, 48, 24, 120, 60, 30, 150

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A050000 and references therein.

Programs

Mathematica

Rest@Nest[Append[#, If[FreeQ[#, r = Quotient[#[[-1]], 2]], r, 5 #[[-1]]]] &, {0, 1}, 55] (* Ivan Neretin, Jul 31 2016 *)