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Search: id:A159923
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| A159923 |
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Rectangular array read by antidiagonals: a(m,n) = greatest non-composite (1 or prime) that divides both m and n. |
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+0
1
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| 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 3, 1, 1, 3, 1, 1, 1, 2, 1, 2, 5, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 2, 1, 3, 1, 2, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 7, 2, 1, 2, 1, 2, 1, 1, 1, 3, 1, 5, 3, 1, 1, 3, 5, 1, 3, 1, 1
(list; table; graph; listen)
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OFFSET
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1,5
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COMMENT
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The array is symmetric along the diagonal; so there is a triangular version with the same amount of information which reads the array along rows up to the diagonal: 1,1,2,1,1,3,1,2,1,2,1,1,1,1,5,1,... [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 29 2009]
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MAPLE
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A159923 := proc(n, m) local g; for g from max(n, m) to 2 by -1 do if isprime(g) and (n mod g) = 0 and (m mod g) = 0 then RETURN(g) ; fi; od: RETURN(1) ; end: for d from 2 to 22 do for m from 1 to d-1 do n := d-m ; printf("%d, ", A159923(n, m)) ; od: od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 29 2009]
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CROSSREFS
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Sequence in context: A053632 A124060 A140194 this_sequence A003989 A091255 A135303
Adjacent sequences: A159920 A159921 A159922 this_sequence A159924 A159925 A159926
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KEYWORD
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nonn,tabl
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AUTHOR
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Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), Apr 26 2009
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 29 2009
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