2,2

G.f.: x^2*(1-x+x^2+x^3-x^4)/(1-x)^5. Differences of A027967. - Ralf Stephan, Feb 07 2004

A column of triangle A026998.

Sequence in context: A077270 A076048 A109414 this_sequence A027660 A002940 A030196

Adjacent sequences: A027963 A027964 A027965 this_sequence A027967 A027968 A027969

nonn

Clark Kimberling (ck6(AT)evansville.edu)