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A106187 Sequence array for central binomial numbers A000984. 3
1, 2, 1, 6, 2, 1, 20, 6, 2, 1, 70, 20, 6, 2, 1, 252, 70, 20, 6, 2, 1, 924, 252, 70, 20, 6, 2, 1, 3432, 924, 252, 70, 20, 6, 2, 1, 12870, 3432, 924, 252, 70, 20, 6, 2, 1, 48620, 12870, 3432, 924, 252, 70, 20, 6, 2, 1, 184756, 48620, 12870, 3432, 924, 252, 70, 20, 6, 2, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums are A006134. Diagonal sums are A106188.

The matrix inverse starts

1;

-2,1;

-2,-2,1;

-4,-2,-2,1;

-10,-4,-2,-2,1;

-28,-10,-4,-2,-2,1;

-84,-28,-10,-4,-2,-2,1;

-264,-84,-28,-10,-4,-2,-2,1;

-858,-264,-84,-28,-10,-4,-2,-2,1;

apparently related to A002420. - R. J. Mathar, Apr 08 2013

LINKS

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

FORMULA

Number triangle T(n, k)=binomial(2(n-k), n-k); Riordan array (1/sqrt(1-4x), x).

EXAMPLE

Table begins

1;

2,1;

6,2,1;

20,6,2,1;

70,20,6,2,1;

MAPLE

A106187 := proc(n, k)

    binomial(2*(n-k), n-k) ;

end proc: # R. J. Mathar, Apr 08 2013

CROSSREFS

Sequence in context: A101024 A124730 A114283 * A110135 A114423 A335109

Adjacent sequences:  A106184 A106185 A106186 * A106188 A106189 A106190

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, Apr 24 2005

STATUS

approved

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Last modified August 15 16:02 EDT 2020. Contains 336505 sequences. (Running on oeis4.)