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 A127767 Inverse of number triangle A(n,k)=if(k<=n,if(n<=2k,1/C(n),0),0), C(n)=A000108(n). 1
 1, 0, 1, 0, -1, 2, 0, 1, -2, 5, 0, 0, 0, -5, 14, 0, -1, 2, 0, -14, 42, 0, 0, 0, 0, 0, -42, 132, 0, 1, -2, 5, 0, 0, -132, 429, 0, 0, 0, 0, 0, 0, 0, -429, 1430, 0, 0, 0, -5, 14, 0, 0, 0, -1430, 4862, 0, 0, 0, 0, 0, 0, 0, 0, 0, -4862, 16796 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 COMMENTS It is conjectured that all elements of the triangle are integers. Row sums give A127768. LINKS EXAMPLE Triangle begins 1, 0, 1, 0, -1, 2, 0, 1, -2, 5, 0, 0, 0, -5, 14, 0, -1, 2, 0, -14, 42, 0, 0, 0, 0, 0, -42, 132, 0, 1, -2, 5, 0, 0, -132, 429, 0, 0, 0, 0, 0, 0, 0, -429, 1430, 0, 0, 0, -5, 14, 0, 0, 0, -1430, 4862, 0, 0, 0, 0, 0, 0, 0, 0, 0, -4862, 16796 Inverse of triangle 1, 0, 1, 0, 1/2, 1/2, 0, 0, 1/5, 1/5, 0, 0, 1/14, 1/14, 1/14, 0, 0, 0, 1/42, 1/42, 1/42, 0, 0, 0, 1/132, 1/132, 1/132, 1/132, 0, 0, 0, 0, 1/429, 1/429, 1/429, 1/429, 0, 0, 0, 0, 1/1430, 1/1430, 1/1430, 1/1430, 1/1430, 0, 0, 0, 0, 0, 1/4862, 1/4862, 1/4862, 1/4862, 1/4862, 0, 0, 0, 0, 0, 1/16796, 1/16796, 1/16796, 1/16796, 1/16796, 1/16796 CROSSREFS Sequence in context: A071502 A074704 A025247 * A055509 A006667 A112570 Adjacent sequences:  A127764 A127765 A127766 * A127768 A127769 A127770 KEYWORD sign,tabl AUTHOR Paul Barry, Jan 28 2007 STATUS approved

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