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

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: A206466 A137434 A175111 * A231706 A189652 A232021

Adjacent sequences: A115187 A115188 A115189 * A115191 A115192 A115193

Keyword

nonn,easy

Author

Wolfdieter Lang, Feb 23 2006

Status

approved