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A128569
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Column 2 of triangle A128567.
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3
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1, 14, 117, 813, 4871, 27743, 151208, 804065, 4185683, 21472005, 108766010, 545507633, 2712801330, 13394412999, 65722444172, 320721839860, 1557502222385, 7530671086667, 36267851679585, 174038009185816
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OFFSET
| 0,2
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COMMENTS
| A128567 is the matrix square of Parker's partition triangle (A047812).
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PROG
| (PARI) {a(n)=local(M); M=matrix(n+3, n+3, r, c, if(r<c, 0, if(r==0, 1, polcoeff(prod(j=r+1, 2*r, 1-q^j)/prod(j=1, r, 1-q^j), (r+1)*(c-1), q)))); (M^2)[n+3, 3]}
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CROSSREFS
| Cf. A128567, A128568 (column 1), A128602 (row sums).
Sequence in context: A178258 A121783 A155647 * A138431 A175874 A006223
Adjacent sequences: A128566 A128567 A128568 * A128570 A128571 A128572
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KEYWORD
| nonn
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AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), Mar 12 2007
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