A203580 - OEIS

A203580

a(n) = Sum{d(i)*2^i: i=0,1,...,m}, where Sum{d(i)*7^i: i=0,1,...,m}=n, d(i)∈{0,1,...,6}

%I #23 Aug 03 2014 14:27:19

%S 0,1,2,3,4,5,6,2,3,4,5,6,7,8,4,5,6,7,8,9,10,6,7,8,9,10,11,12,8,9,10,

%T 11,12,13,14,10,11,12,13,14,15,16,12,13,14,15,16,17,18,4,5,6,7,8,9,10,

%U 6,7,8,9,10,11,12,8,9,10,11,12,13,14,10,11,12,13,14

%N a(n) = Sum{d(i)*2^i: i=0,1,...,m}, where Sum{d(i)*7^i: i=0,1,...,m}=n, d(i)∈{0,1,...,6}

%C Change-of-base sequence 7->2.

%H Clark Kimberling, <a href="/A203580/b203580.txt">Table of n, a(n) for n = 0..1000</a>

%F a(0)=0, a(n)=2*a(n/7) if n==0 (mod 7), a(n)=a(n-1)+1 otherwise.

%t t = Table[FromDigits[RealDigits[n, 7], 2], {n, 0, 100}] (* _Clark Kimberling_, Aug 03 2012 *)

%Y Cf. A033044.

%K nonn,base

%O 0,3

%A _Karol Bacik_, Jan 03 2012