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Search: id:A112519
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| A112519 |
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Riordan array (1,xc(x)*c(-xc(x))), c(x) the g.f. of A000108. |
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+0
4
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| 1, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 1, 4, 0, 1, 0, 12, 2, 6, 0, 1, 0, 14, 28, 3, 8, 0, 1, 0, 100, 32, 48, 4, 10, 0, 1, 0, 180, 249, 54, 72, 5, 12, 0, 1, 0, 990, 440, 455, 80, 100, 6, 14, 0, 1, 0, 2310, 2552, 792, 726, 110, 132, 7, 16, 0, 1, 0, 10920, 5876, 4836, 1248, 1070, 144, 168, 8, 18
(list; table; graph; listen)
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OFFSET
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0,8
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COMMENT
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Row sums are A112520. Second column is essentially A055392. Inverse is A112517. Riordan array product (1,xc(x))*(1,xc(-x)).
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FORMULA
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Riordan array (1, (sqrt(3-2*sqrt(1-4x))-1)/2); Number triangle T(0, 0)=1, T(n, k)=sum{j=0..n, (k/n)(-1)^(j-k)C(2n-j-1, n-j)C(2j-k-1, j-k)}.
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EXAMPLE
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Triangle begins
1;
0,1;
0,0,1;
0,2,0,1;
0,1,4,0,1;
0,12,2,6,0,1;
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CROSSREFS
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Sequence in context: A004173 A066745 A112517 this_sequence A091728 A108069 A089734
Adjacent sequences: A112516 A112517 A112518 this_sequence A112520 A112521 A112522
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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), Sep 09 2005
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