The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #4 Oct 01 2012 12:34:36
%S 0,1,2,5,9,18,34,71,139,280,555,1119,2228,4462,8907,17835,35634,71288,
%T 142507,285077,570013,1140102,2279924,4560040,9119516,18239335,
%U 36477548,72955801,145909351,291819915,583635336,1167273283
%N Number of strings of n 2's and 3's having a tail of length 1.
%Y This is the k=1 column (the second column) of the triangle in A217209.
%K nonn
%O 1,3
%A _N. J. A. Sloane_, Oct 01 2012