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Search: id:A132425
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| A132425 |
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a(1)=1. a(2)=2. For n >= 3, a(n) is the smallest integer which is > a(n-1), is not coprime to a(n-1) and is such that a(n)-a(n-1) does not equal a(m)-a(m-1) for any m < n. |
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+0
2
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| 1, 2, 4, 8, 14, 21, 24, 32, 42, 51, 63, 77, 88, 104, 117, 132, 150, 155, 175, 196, 218, 242, 268, 296, 326, 358, 392, 427, 469, 518, 554, 592, 629, 646, 665, 690, 713, 744, 771, 804, 843, 888, 928, 957, 1001, 1053, 1101, 1152, 1198, 1248, 1302, 1358, 1416, 1473
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Is {a(n+1)-a(n)} 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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MATHEMATICA
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a = {1, 2}; For[n = 1, n < 1500, n++, n = a[[ -1]]; c = 0; While[c == 0, n++; If[GCD[n, a[[ -1]]] > 1, b = 0; For[j = 1, j < Length[a], j++, If[a[[j + 1]] - a[[j]] == n - a[[ -1]], b = 1]]; If[b == 0, AppendTo[a, n]; c = 1]]]]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Oct 21 2007
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CROSSREFS
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Cf. A089781, A132426.
Sequence in context: A002132 A140164 A160730 this_sequence A154264 A155506 A014206
Adjacent sequences: A132422 A132423 A132424 this_sequence A132426 A132427 A132428
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Aug 20 2007
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Oct 21 2007
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