login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

a(1) = 16; a(n+1) = sum of a(n) and (a(n) written in base 2 and reversed).
0

%I #4 Mar 30 2012 17:30:43

%S 16,17,34,51,102,153,306,459,882,1197,2646,4347,11484,15273,24864,

%T 25443,50886,76329,152274,229371,458742,688113,1277910,2162607,

%U 6193008,6684333,12631680,12729219,25434054,38529033,76302162,115562715

%N a(1) = 16; a(n+1) = sum of a(n) and (a(n) written in base 2 and reversed).

%D S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 125.

%e To get a(2) note that 16 = 10000 in base 2, reversing gives 00001, or 1 and so a(2) = 16 + 1 = 17.

%t a[1] = 16; a[n_] := Block[{b = IntegerDigits[ a[n - 1], 2]}, FromDigits[ b + Reverse[b], 2]]; Table[ a[n], {n, 1, 35}]

%K nonn,easy,base

%O 1,1

%A _N. J. A. Sloane_, May 19 2002

%E More terms from _Robert G. Wilson v_, May 20 2002