A115190 - OEIS

A115190

Fourth diagonal (M=4) of triangle A115154 (called Y(3,1)).

1, 121, 1762, 20989, 235543, 2588641, 28259704, 308277688, 3369314986, 36937817182, 406378312834, 4487124168115, 49722977591155, 552884158181785, 6167643983348920, 69012419067802540, 774413615153430670

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..16.

FORMULA

a(n)= A115154(n+3,n+1), n>=0.

Recurrence: a(n)= b(n) - 9*(b(n-1)-b(n-2)), with b(n):=A064063(n+4), n>=0.

G.f.: ((-3+18*x+2*x^3) + 3*(1-9*x+9*x^2)*c(3*x))/((2+x)*x^3), with the o.g.f. c(x) of A000108 (Catalan).

EXAMPLE

a(0)= 1 = 190 - 9*(25-4); a(2) = 1762 = 14506 - 9*(1606-190).

CROSSREFS

Sequence in context: A137434 A175111 A375917 * A231706 A372964 A189652

Adjacent sequences: A115187 A115188 A115189 * A115191 A115192 A115193

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang, Feb 23 2006

STATUS

approved