OFFSET
0,3
LINKS
Emeric Deutsch, Emanuele Munarini, Simone Rinaldi, Skew Dyck paths, area, and superdiagonal bargraphs, Journal of Statistical Planning and Inference, Vol. 140, Issue 6, June 2010, pp. 1550-1562.
FORMULA
g.f.: (1-10*x+13*x^2-(1-7*x)*sqrt(1-6*x+5*x^2))/2/(5*x-1) .
D-finite with recurrence: n*(n+3)*a(n) +(-11*n^2-24*n+55)*a(n-1) +5*(7*n^2+9*n-71)*a(n-2) -25*(n-4) *(n+4)*a(n-3)=0.
MAPLE
g := (1-10*x+13*x^2-(1-7*x)*sqrt(1-6*x+5*x^2))/2/(5*x-1) ;
taylor(g, x=0, 40) ;
gfun[seriestolist](%) ;
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Jun 21 2018
STATUS
approved