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A026001 a(n) = T(3n,n), where T = Delannoy triangle (A008288). 2
1, 7, 85, 1159, 16641, 246047, 3707509, 56610575, 872893441, 13560999991, 211939849045, 3328419072535, 52481589415425, 830317511708367, 13174519143904245, 209559710593266719, 3340604559333629953, 53354776911196959335, 853607938952248383829, 13677336690921351929767 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

If the Delannoy triangle is defined by the Maple code in A008288, this is A008288(n, 3*n-2), n >= 1. - N. J. A. Sloane

LINKS

Table of n, a(n) for n=0..19.

FORMULA

G.f.: F(G^(-1)(x)) where F = (2-t)/(3*t^2-8*t+2) and G = t*(t-1)^3/(t-2). - Mark van Hoeij, Oct 30 2011

MAPLE

F := (2-t)/(3*t^2-8*t+2);  G := t*(t-1)^3/(t-2);  Ginv := RootOf(numer(G-x), t); ogf := series(eval(F, t=Ginv), x=0, 25); # Mark van Hoeij, Oct 30 2011

CROSSREFS

Sequence in context: A126344 A193578 A309187 * A064089 A216698 A317353

Adjacent sequences:  A025998 A025999 A026000 * A026002 A026003 A026004

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Corrected and extended by N. J. A. Sloane, Oct 29 2006

STATUS

approved

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Last modified October 23 16:46 EDT 2019. Contains 328373 sequences. (Running on oeis4.)