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A115292 Correlation triangle for (1+x)^3/(1-x). 4
1, 4, 4, 7, 17, 7, 8, 32, 32, 8, 8, 39, 66, 39, 8, 8, 40, 88, 88, 40, 8, 8, 40, 95, 130, 95, 40, 8, 8, 40, 96, 152, 152, 96, 40, 8, 8, 40, 96, 159, 194, 159, 96, 40, 8, 8, 40, 96, 160, 216, 216, 160, 96, 40, 8, 8, 40, 96, 160, 223, 258, 223, 160, 96, 40, 8 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums are A115293. Diagonal sums are A115294. T(2n,n) is A115295. T(2n,n)-T(2n,n+1) is 1,10,27,35,35,35,... The transform of (-1)^n by this matrix is 1,0,-3,0,4,0,-4,0,4,...

LINKS

Table of n, a(n) for n=0..65.

FORMULA

G.f.: (1+x)^3*(1+xy)^3/((1-x)(1-x*y)(1-x^2*y)); Number triangle T(n, k)=sum{j=0..n, [j<=k]*A115291(k-j)*[j<=n-k]*A115291(n-k-j)}.

EXAMPLE

Triangle begins

1;

4, 4;

7, 17, 7;

8, 32, 32, 8;

8, 39, 66, 39, 8;

8, 40, 88, 88, 40, 8;

8, 40, 95, 130, 95, 40, 8;

8, 40, 96, 152, 152, 96, 40, 8;

CROSSREFS

Sequence in context: A036605 A183541 A238389 * A202676 A173324 A183492

Adjacent sequences:  A115289 A115290 A115291 * A115293 A115294 A115295

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, Jan 19 2006

STATUS

approved

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Last modified February 19 08:37 EST 2018. Contains 299330 sequences. (Running on oeis4.)