A073061 a(1)=1, a(2k)=2*a(k), a(2k+1)=3*a(k).

1, 2, 3, 4, 6, 6, 9, 8, 12, 12, 18, 12, 18, 18, 27, 16, 24, 24, 36, 24, 36, 36, 54, 24, 36, 36, 54, 36, 54, 54, 81, 32, 48, 48, 72, 48, 72, 72, 108, 48, 72, 72, 108, 72, 108, 108, 162, 48, 72, 72, 108, 72, 108, 108, 162, 72, 108, 108, 162, 108, 162, 162, 243, 64, 96, 96

Offset

1,2

Comments

All terms are 3-smooth (see A003586). The number of appearances of 2^a * 3^b is binomial(a+b,a). - Ivan Neretin, Jun 05 2016

Links

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

Formula

There is no general formula but a(5+4k)=a(6+4k), a(A029744(k))=A029744(k), sum(k=1, n, a(k)) is asymptotic to C*n^2*Log(n) with C=0.23...

2^A023416(n) * 3^(A000120(n)-1), n>0. - Ralf Stephan, Mar 18 2004

Mathematica

Fold[Join[#1, {2 #1[[#2]], 3 #1[[#2]]}] &, {1}, Range[33]] (* Ivan Neretin, Jun 05 2016 *)

Crossrefs

Sequence in context: A157450 A195013 A079667 * A300526 A006874 A357476

Adjacent sequences: A073058 A073059 A073060 * A073062 A073063 A073064

Keyword

nonn

Author

Benoit Cloitre, Aug 16 2002

Status

approved