OFFSET
0,3
LINKS
Paul Barry, On Integer-Sequence-Based Constructions of Generalized Pascal Triangles, Journal of Integer Sequences, Vol. 9 (2006), Article 06.2.4.
FORMULA
a(n) = {1 / (n+1)_q} {2 n choose n}_q.
MATHEMATICA
Table[3 QBinomial[2n, n, -2]/(1 - (-2)^(n+1)), {n, 0, 20}] (* Vladimir Reshetnikov, Sep 16 2016 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved