Is it obvious from the comments to http://www.research.att.com/~njas/sequences/A001399 1, 1, 2, 3, 4, 5, 7, 8, 10, 12, 14, 16, 19, 21, 24, 27, 30, 33, 37, 40, 44, 48, 52 that it's the number of nonnegative x,y integer solutions to 2*x+3*y <= n (empirical) -- rhhardin at mindspring.com rhhardin at att.net (either)