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| A020921
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Triangle read by rows: T(m,n) = number of solutions to 1 <= a(1) < a(2) < ... < a(m) <= n, where gcd( a(1), a(2), ..., a(m), n) = 1.
(history;
published version)
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#34 by Joerg Arndt at Tue Mar 24 12:37:41 EDT 2020
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#33 by Michel Marcus at Tue Mar 24 05:30:07 EDT 2020
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#32 by F. Chapoton at Tue Mar 24 05:18:00 EDT 2020
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#31 by F. Chapoton at Tue Mar 24 05:17:51 EDT 2020
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(SageMath) Function DivisorTriangle is defined in A327029.
(Sage) # uses[DivisorTriangle from A327029]
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approved
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Discussion
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| F. Chapoton: formal link syntax for sage code
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#30 by N. J. A. Sloane at Sat Aug 24 21:24:44 EDT 2019
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#29 by Peter Luschny at Sat Aug 24 15:26:54 EDT 2019
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#28 by Peter Luschny at Sat Aug 24 07:33:43 EDT 2019
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(SageMath) Function DivisorTriangle is defined in A327029.
DivisorTriangle(moebius, binomial, 13) # Peter Luschny, Aug 24 2019
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Cf. A327029.
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#27 by Jon E. Schoenfield at Sat Apr 13 17:31:06 EDT 2019
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#26 by Jon E. Schoenfield at Sat Apr 13 17:30:59 EDT 2019
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Triangle read by rows: T(m,n) = number of solutions to 1 <= a(1) < a(2) < ... < a(m) <= n, where GCDgcd( a(1), a(2), ....), ..., a(m), n) = 1.
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#25 by N. J. A. Sloane at Thu Sep 07 12:15:10 EDT 2017
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