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A158824
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Triangle T(n,1) = A000292(n) and T(n,k) = (k-1)*(k-n-1)*(k-n-2)/2 if 2<=k<=n.
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2
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1, 4, 1, 10, 3, 2, 20, 6, 6, 3, 35, 10, 12, 9, 4, 56, 15, 20, 18, 12, 5, 84, 21, 30, 30, 24, 15, 6, 120, 28, 42, 42, 40, 30, 18, 7, 165, 36, 56, 63, 60, 50, 36, 21, 8, 220, 45, 72, 84, 84, 75, 60, 42, 24, 9, 286, 55, 90, 108, 112, 105, 90, 70, 48, 27, 10
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OFFSET
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1,2
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COMMENTS
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The triangle can also be defined by multiplying the triangles A(n,k)=1 and A158823(n,k), that is, this here are the partial column sums of A158823.
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LINKS
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Table of n, a(n) for n=1..66.
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EXAMPLE
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First few rows of the triangle =
1;
4, 1;
10, 3, 2;
20, 6, 6, 3;
35, 10, 12, 9, 4;
56, 15, 20, 18, 12, 5;
84, 21, 30, 30, 24, 15, 6;
120, 28, 42, 45, 40, 30, 18, 7;
165, 36, 56, 63, 60, 50, 36, 21, 8;
220, 45, 72, 84, 84, 75, 60, 42, 24, 9;
286, 55, 90, 108, 112, 105, 90, 70, 48, 27, 10;
364, 66, 110, 135, 144, 140, 126, 105, 80, 54, 30, 11;
455, 78, 132, 165, 180, 180, 168, 147, 120, 90, 60, 33, 12;
...
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CROSSREFS
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Cf. A104633, A062707, A158823, A000332 (row sums).
Sequence in context: A006370 A262370 A108759 * A039806 A030320 A104713
Adjacent sequences: A158821 A158822 A158823 * A158825 A158826 A158827
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KEYWORD
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nonn,tabl,easy
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AUTHOR
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Gary W. Adamson & Roger L. Bagula, Mar 28 2009
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STATUS
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approved
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