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Search: id:A121434
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| A121434 |
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Matrix inverse of triangle A098568, where A098568(n, k) = C( (k+1)*(k+2)/2 + n-k-1, n-k) for n>=k>=0. |
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4
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| 1, 0, 1, 0, -1, 1, 0, 2, -3, 1, 0, -7, 12, -6, 1, 0, 37, -67, 39, -10, 1, 0, -268, 498, -311, 95, -15, 1, 0, 2496, -4701, 3045, -1015, 195, -21, 1, 0, -28612, 54298, -35901, 12560, -2675, 357, -28, 1, 0, 391189, -745734, 499157, -179717, 40635, -6097, 602, -36, 1, 0, -6230646, 11911221, -8034267, 2945010
(list; table; graph; listen)
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OFFSET
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0,8
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FORMULA
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(1) T(n,k) = (-1)^(n-k)*[A107876^(k*(k+1)/2)](n,k); i.e., column k equals signed column k of A107876^(k*(k+1)/2). G.f.s for column k: (2) 1 = Sum_{j>=0} T(j+k,k)*x^j/(1-x)^( j*(j+1)/2) + j*k + k*(k+1)/2); (3) 1 = Sum_{j>=0} T(j+k,k)*x^j*(1+x)^( j*(j-1)/2) + j*k + k*(k+1)/2).
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EXAMPLE
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Triangle begins:
1;
0, 1;
0, -1, 1;
0, 2, -3, 1;
0, -7, 12, -6, 1;
0, 37, -67, 39, -10, 1;
0, -268, 498, -311, 95, -15, 1;
0, 2496, -4701, 3045, -1015, 195, -21, 1;
0, -28612, 54298, -35901, 12560, -2675, 357, -28, 1;
0, 391189, -745734, 499157, -179717, 40635, -6097, 602, -36, 1; ...
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PROGRAM
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(PARI) /* Matrix Inverse of A098568 */ {T(n, k)=local(M=matrix(n+1, n+1, r, c, if(r>=c, binomial((c-1)*(c-2)/2+r-2, r-c)))); return((M^-1)[n+1, k+1])} (PARI) /* Obtain by G.F. */ {T(n, k)=polcoeff(1-sum(j=0, n-k-1, T(j+k, k)*x^j/(1-x+x*O(x^n))^(j*(j+1)/2+j*k+k*(k+1)/2)), n-k)}
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CROSSREFS
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Cf. A098568, A107876; unsigned columns: A107877, A107887.
Sequence in context: A005210 A048994 A132393 this_sequence A137329 A004579 A081371
Adjacent sequences: A121431 A121432 A121433 this_sequence A121435 A121436 A121437
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KEYWORD
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sign,tabl
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Aug 27 2006
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