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Search: id:A069740
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| A069740 |
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Let M_n be the n X n matrix M_(i,j)=1/(i+j+ij); a(n) is the numerator of det(M_n). |
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1
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| 1, 1, 1, 1, 4, 1, 64, 4, 65536, 512, 33554432, 65536, 68719476736, 6442450944, 9007199254740992, 281474976710656, 220326730624766167090200576, 340010386766614455386112, 486777830487640090174734030864384
(list; graph; listen)
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OFFSET
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1,5
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COMMENT
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Is a(n) always of the form 2^u*3^v?
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PROGRAM
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(PARI) for(n=1, 70, print1(numerator(matdet(matrix(n, n, i, j, 1/(i*j+i+j)))), ", "))
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CROSSREFS
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Sequence in context: A060627 A113101 A113112 this_sequence A114917 A100864 A164797
Adjacent sequences: A069737 A069738 A069739 this_sequence A069741 A069742 A069743
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 21 2002
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