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Search: id:A105868
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| A105868 |
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Number triangle C(n,k)C(k,n-k). |
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+0
4
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| 1, 0, 1, 0, 2, 1, 0, 0, 6, 1, 0, 0, 6, 12, 1, 0, 0, 0, 30, 20, 1, 0, 0, 0, 20, 90, 30, 1, 0, 0, 0, 0, 140, 210, 42, 1, 0, 0, 0, 0, 70, 560, 420, 56, 1, 0, 0, 0, 0, 0, 630, 1680, 756, 72, 1, 0, 0, 0, 0, 0, 252, 3150, 4200, 1260, 90, 1, 0, 0, 0, 0, 0, 0, 2772, 11550, 9240, 1980, 110, 1, 0, 0
(list; table; graph; listen)
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OFFSET
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0,5
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COMMENT
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Row sums are the central trinomial coefficients A002426. Diagonal sums are A105869.
Product of A007318 and this sequence is A008459.
Coefficient array for polynomials P(n,x)=x^n*F(1/2-n/2,-n/2;1;4/x). [From Paul Barry (pbarry(AT)wit.ie), Oct 04 2008]
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EXAMPLE
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Triangle begins
1;
0,1;
0,2,1;
0,0,6,1;
0,0,6,12,1;
0,0,0,30,20,1;
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CROSSREFS
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Cf. A063007, A105870.
Sequence in context: A136129 A034093 A057150 this_sequence A057275 A057271 A021480
Adjacent sequences: A105865 A105866 A105867 this_sequence A105869 A105870 A105871
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Apr 23 2005
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