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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
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
KEYWORD
easy,nonn,tabl
AUTHOR
Paul Barry, Apr 24 2005
STATUS
approved

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Last modified March 28 11:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)