A050092 a(n) = floor(a(n-1)/3) if this is positive and not yet in the sequence, otherwise a(n) = 7*a(n-1).

1, 7, 2, 14, 4, 28, 9, 3, 21, 147, 49, 16, 5, 35, 11, 77, 25, 8, 56, 18, 6, 42, 294, 98, 32, 10, 70, 23, 161, 53, 17, 119, 39, 13, 91, 30, 210, 1470, 490, 163, 54, 378, 126, 882, 6174, 2058, 686, 228, 76, 532, 177, 59, 19, 133, 44, 308

Offset

1,2

Links

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

Mathematica

Rest@Nest[Append[#, If[FreeQ[#, r = Quotient[#[[-1]], 3]], r, 7 #[[-1]]]] &, {0, 1}, 55] (* Ivan Neretin, Jul 31 2016 *)

Prog

(PARI) first(n)=my(v=vector(n), t); v[1]=1; for(i=2, n, t=v[i-1]\3; if(t<2, v[i]=7*v[i-1]; next); for(j=1, i-1, if(v[j]==t, v[i]=7*v[i-1]; next(2))); v[i]=t); v \\ Charles R Greathouse IV, Jul 31 2016

Crossrefs

Cf. A050000 and references therein.

Sequence in context: A323995 A040048 A070429 * A293452 A030406 A336194

Adjacent sequences: A050089 A050090 A050091 * A050093 A050094 A050095

Keyword

nonn

Author

Clark Kimberling

Status

approved