OFFSET
0,3
EXAMPLE
G.f. A(x) = 1 + x + 3*x^2 + 12*x^3 + 56*x^4 + 288*x^5 + 1584*x^6 + 9153*x^7 + 54940*x^8 + ...
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Mar 20 2018
STATUS
approved