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Search: id:A067550
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| 1, 2, 10, 90, 1260, 25200, 680400, 23814000, 1047816000, 56582064000, 3677834160000, 283193230320000, 25487390728800000, 2650688635795200000, 315431947659628800000, 42583312934049888000000, 6472663565975582976000000
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OFFSET
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1,2
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COMMENT
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Determinant of n X n matrix whose diagonal are the first n triangular numbers and all other elements are 1's.
a(n+1)/a(n) = A000096(n) = n(n+3)/2. - Alexander Adamchuk (alex(AT)kolmogorov.com), May 20 2006
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EXAMPLE
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The determinant begins:
1 1 1 1 1 1 1 ...
1 3 1 1 1 1 1 ...
1 1 6 1 1 1 1 ...
1 1 1 10 1 1 1 ...
1 1 1 1 15 1 1 ...
1 1 1 1 1 21 1 ...
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MATHEMATICA
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Table[ Det[ DiagonalMatrix[ Table[ i(i + 1)/2 - 1, {i, 1, n} ] ] + 1 ], {n, 1, 20} ]
Table[(n-1)!(n+2)!/3/2^n, {n, 1, 20}] - Alexander Adamchuk (alex(AT)kolmogorov.com), May 20 2006
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CROSSREFS
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Cf. A000096.
Adjacent sequences: A067547 A067548 A067549 this_sequence A067551 A067552 A067553
Sequence in context: A060350 A096658 A055779 this_sequence A086587 A082472 A095937
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 28 2002
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