OFFSET
0,2
LINKS
Stefano Spezia, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).
FORMULA
a(n) = 1 + 6*n + 20*n^2 + 48*n^3 + 90*n^4 + 132*n^5 + 132*n^6, compare to row n = 6 of Catalan triangle A009766.
G.f.: (1 + 422*x + 11607*x^2 + 43940*x^3 + 34063*x^4 + 4950*x^5 + 57*x^6)/(1 - x)^7.
E.g.f.: exp(x)*(1 + 428*x + 6866*x^2 + 15768*x^3 + 9990*x^4 + 2112*x^5 + 132*x^6). - Stefano Spezia, Jul 24 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Sep 13 2001
STATUS
approved