If, after constructing a Difference Table, no clear pattern emerges, turn the paper through an Angle of 60° and compute a new table. If necessary, repeat the process. Each Rotation reduces Powers by 1, so the sequence multiplied by any Polynomial in is reduced to 0s by a -fold difference fan.
References
Conway, J. H. and Guy, R. K. ``Jackson's Difference Fans.'' In The Book of Numbers. New York:
Springer-Verlag, pp. 84-85, 1996.