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A305555
Sum of the areas of all L-elevated skew paths of semi-length n.
0
0, 0, 3, 19, 106, 564, 2935, 15091, 77037, 391433, 1982573, 10018605, 50541372, 254637294, 1281605541, 6445146105, 32390909850, 162695554860, 816825463045, 4099345475605, 20566288883610, 103150972979000, 517229100535265, 2592974460838005, 12996619961409245, 65131180719470549, 326348682636203655, 1634993474319839431
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
Sequence in context: A373804 A375028 A151539 * A323919 A089164 A323290
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Jun 21 2018
STATUS
approved