A215088 a(n)=Sum{d(i)*2^i: i=0,1,...,m}, where Sum{d(i)*5^i: i=0,1,...,m} is the base 5 representation of n.

0, 1, 2, 3, 4, 2, 3, 4, 5, 6, 4, 5, 6, 7, 8, 6, 7, 8, 9, 10, 8, 9, 10, 11, 12, 4, 5, 6, 7, 8, 6, 7, 8, 9, 10, 8, 9, 10, 11, 12, 10, 11, 12, 13, 14, 12, 13, 14, 15, 16, 8, 9, 10, 11, 12, 10, 11, 12, 13, 14, 12, 13, 14, 15, 16, 14, 15, 16, 17, 18, 16, 17, 18, 19, 20, 12, 13, 14, 15, 16, 14, 15, 16, 17, 18, 16, 17, 18, 19, 20, 18, 19, 20, 21, 22, 20, 21, 22, 23

Offset: 0

Author

Clark Kimberling, Aug 02 2012

Keywords

• nonn
• easy

Links

• Clark Kimberling, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A033042.

Programs

Mathematica

t = Table[FromDigits[RealDigits[n, 5], 2], {n, 0, 100}]

Formula

a(n) = 2*a(n/5) if n = 0 mod 5; otherwise, a(n) = a(n-1) + 1. - Clark Kimberling, Aug 03 2012