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%I #3 Dec 05 2013 19:55:14
%S 1,2,0,4,32,0,16,8,0,64,128,0,256,2048,0,0,0,0,4096,8192,0,16384,0,0,
%T 65536,32768,0,0,524288,0,1048576,0,0,0,134217728,0,16777216,0,0,
%U 67108864,8388608,0,268435456,0,0,4398046511104,2147483648,0,0
%N Smallest power of 2 with digital sum (A007953) n, or 0 if no such number exists.
%C a(3k)=0. In general about half the entries are nonzero.
%e Both 2^4=16 and 2^10=1024 have a digital sum of 7 but 2^4 is the smaller so it is the one presented.
%t a = Table[0, {50}]; Do[b = Plus @@ IntegerDigits[2^n]; If[b < 51 && a[[b]] == 0, a[[b]] = 2^n], {n, 0, 10^4}]; a
%Y Cf. A007632.
%K base,nonn
%O 1,2
%A _Amarnath Murthy_, Apr 02 2002
%E Edited by _Robert G. Wilson v_, Nov 05 2002