A144526 Denominators of expansion of exp(1-sqrt(1-3*x)).
1, 2, 4, 16, 128, 640, 5120, 71680, 573440, 2293760, 6553600, 504627200, 1153433600, 209924915200, 2938948812800, 58778976256000, 1880927240192000, 415269650432000, 255806104666112000, 15260018802688000, 194412639546245120000, 418734915945758720000
Offset: 0
Examples
1 + (3/2)*x + (9/4)*x^2 + (63/16)*x^3 + (999/128)*x^4 + (10773/640)*x^5 + (196911/5120)*x^6 + ...