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A051289
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Triangular array T read by rows: T(n,k)=P(2n+1,n,2k+1), where P(n,k,c)=number of vectors (x(1),x(2,),...,x(n)) of k 1's and n-k 0's such that x(i)=x(n+1-i) for exactly c values of i.
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0
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1, 2, 1, 4, 4, 2, 8, 12, 12, 3, 16, 32, 48, 24, 6, 32, 80, 160, 120, 60, 10, 64, 192, 480, 480, 360, 120, 20, 128, 448, 1344, 1680, 1680, 840, 280, 35, 256, 1024, 3584, 5376, 6720, 4480, 2240, 560, 70, 512, 2304, 9216, 16128, 24192
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OFFSET
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0,2
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COMMENTS
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P(n,k,n) counts palindromes.
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LINKS
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FORMULA
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E.g.f.: exp(2*y)*(BesselI(0, 2*x*y)+BesselI(1, 2*x*y)). - Vladeta Jovovic, Dec 15 2004
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EXAMPLE
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Triangle begins:
1;
2, 1;
4, 4, 2;
8, 12, 12, 3;
16, 32, 48, 24, 6;
...
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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