A044451 - OEIS

%I #5 Mar 30 2012 18:56:44

%S 9,25,39,41,57,73,89,103,105,121,137,159,167,169,185,201,217,231,233,

%T 249,265,281,295,297,313,329,345,359,361,377,393,415,423,425,441,457,

%U 473,487,489,505,521,537,551,553,569,639,649

%N Numbers n such that string 2,1 occurs in the base 4 representation of n but not of n+1.

%K nonn,base

%O 1,1

%A _Clark Kimberling_