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Search: id:A125703
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| A125703 |
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Table read by antidiagonals: row n contains the positive integers (in order) which are coprime to the n-th prime and do not occur in earlier rows. |
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| 1, 2, 3, 6, 4, 5, 30, 12, 8, 7, 210, 60, 18, 10, 9, 2310, 420, 90, 24, 14, 11, 30030, 4620, 630, 120, 36, 16, 13, 510510, 60060, 6930, 840, 150, 42, 20, 15, 9699690, 1021020, 90090, 9240, 1050, 180, 48, 22, 17, 223092870, 19399380, 1531530, 120120, 11550
(list; table; graph; listen)
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OFFSET
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1,2
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COMMENT
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Row n, for n >= 2, contains the multiples of (product{k=1 to n-1} p(k)) that are coprime to p(n), where p(k) is the k-th prime. The concatenated sequence is a permutation of the positive integers.
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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FORMULA
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T(n,m) = A002110(n-1)*A125704(n,m). - Ray Chandler
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EXAMPLE
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The beginning of the table:
1,3,5,7,9,11,...
2,4,8,10,14,16,20,...
6,12,18,24,36,...
30,60,90,120,150,...
210,420,630,840,...
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MATHEMATICA
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f[n_, m_] := Block[{p = Prime[n], x = Product[Prime[i], {i, n - 1}], k = 0, c = m}, While[c > 0, k += x; While[GCD[k, p] > 1, k += x]; c--; ]; k]; Table[f[d + 1 - m, m], {d, 10}, {m, d}] // Flatten(*Chandler*)
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CROSSREFS
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Sequence in context: A064470 A127915 A072637 this_sequence A156688 A019567 A098286
Adjacent sequences: A125700 A125701 A125702 this_sequence A125704 A125705 A125706
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KEYWORD
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nonn,tabl
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AUTHOR
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Leroy Quet Jan 31 2007
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Feb 07 2007
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