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Search: id:A129455
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| 1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 256, 384, 256, 1, 1, 5, 640, 640, 5, 1, 1, 1146617856, 2866544640, 244611809280, 2866544640, 1146617856, 1, 1, 7, 4013162496, 6688604160, 6688604160, 4013162496, 7, 1, 1, 35184372088832, 123145302310912
(list; table; graph; listen)
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OFFSET
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0,5
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COMMENT
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It appears that the T(n,k) are always integers. This would follow from the conjectured prime factorization given in A129454. Calculation suggests that the binomial coefficients C(n,k) divide T(n,k) and that T(n,k)/C(n,k) are perfect sixth powers.
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FORMULA
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T(n,k) = product_{h=1..n}product_{i=1..n}product_{j=1..n} gcd(h,i,j)/(product_{h=1..n-k}product_{i=1..n-k}product_{j=1..n-k} gcd(h,i,j)*product_{h=1..k}product_{i=1..k}product_{j=1..k} gcd(h,i,j)).
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EXAMPLE
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Triangle starts:
1
1 1
1 2 1
1 3 3 1
1 256 384 256 1
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CROSSREFS
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Cf. A007318, A092287, A129453, A129454.
Sequence in context: A129439 A141542 A129453 this_sequence A067924 A056670 A030189
Adjacent sequences: A129452 A129453 A129454 this_sequence A129456 A129457 A129458
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KEYWORD
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nonn,tabl
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AUTHOR
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Peter Bala (pbala(AT)toucansurf.com), Apr 16 2007
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