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A320637
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Regular triangle read by rows: T(n,k) = Lcm_{m=k..n} d(n,k) where d(n,k) is the denominator of the unsigned Stirling1(n,k)*k!/n! for 0 <= k <= n.
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0
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1, 1, 1, 1, 2, 1, 1, 6, 1, 1, 1, 12, 12, 2, 1, 1, 60, 12, 4, 1, 1, 1, 60, 180, 8, 6, 2, 1, 1, 420, 180, 120, 6, 6, 1, 1, 1, 840, 5040, 240, 240, 6, 4, 2, 1, 1, 2520, 5040, 15120, 240, 144, 4, 12, 1, 1, 1, 2520, 25200, 30240, 15120, 288, 240, 24, 3, 2, 1
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OFFSET
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0,5
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LINKS
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EXAMPLE
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Triangle begins:
1,
1, 1,
1, 2, 1,
1, 6, 1, 1,
1, 12, 12, 2, 1,
1, 60, 12, 4, 1, 1,
1, 60, 180, 8, 6, 2, 1,
1, 420, 180, 120, 6, 6, 1, 1,
...
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PROG
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(PARI) d(n, k) = denominator(abs(stirling(n, k, 1))*k!/n!);
T(n, k) = my(x = 1); for (m=k, n, x = lcm(x, d(m, k))); x;
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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