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 A105619 Matrix inverse of triangle A105615. 2
 1, -2, 1, -2, -4, 1, -10, -2, -6, 1, -74, -10, -2, -8, 1, -706, -74, -10, -2, -10, 1, -8162, -706, -74, -10, -2, -12, 1, -110410, -8162, -706, -74, -10, -2, -14, 1, -1708394, -110410, -8162, -706, -74, -10, -2, -16, 1, -29752066, -1708394, -110410, -8162, -706, -74, -10, -2, -18, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Except for the initial few terms, all columns are equal to negative A000698 (related to double factorials). LINKS EXAMPLE Triangle begins: 1; -2,1; -2,-4,1; -10,-2,-6,1; -74,-10,-2,-8,1; -706,-74,-10,-2,-10,1; -8162,-706,-74,-10,-2,-12,1; -110410,-8162,-706,-74,-10,-2,-14,1; -1708394,-110410,-8162,-706,-74,-10,-2,-16,1; ... PROG (PARI) {T(n, k)=if(n=j, if(m==j, 1, if(m==j+1, -2*j, polcoeff(1/sum(i=0, m-j, (2*i)!/i!/2^i*x^i)+O(x^m), m-j)))))[n+1, k+1])} CROSSREFS Cf. A105615, A000698, A105620 (matrix square-root). Sequence in context: A177701 A119765 A077901 * A121439 A009205 A086754 Adjacent sequences:  A105616 A105617 A105618 * A105620 A105621 A105622 KEYWORD sign,tabl AUTHOR Paul D. Hanna, Apr 16 2005 STATUS approved

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Last modified May 19 00:20 EDT 2013. Contains 225428 sequences.