OFFSET
0,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..23712
MATHEMATICA
okQ[n_] := Module[{bb = IntegerDigits[n, 2], cnt=0}, For[k=1, k <= Length[ bb], k++, cnt = cnt + If[bb[[k]]==1, 1, -1]; okQ[0] = True; If[cnt < 0, Return[False]]]; cnt==0]; Select[Range[0, 10^4], okQ] // Differences (* Jean-François Alcover, Mar 02 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 14 2003
STATUS
approved