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A112598
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a(1)=a(2)=1. For n >= 3, a(n) is smallest integer > a(n-1) such that GCD(a(n),a(n-1)+a(n-2)) > 1.
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0
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1, 1, 2, 3, 5, 6, 11, 17, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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FORMULA
| For n >= 9, a(n) = 2n.
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EXAMPLE
| 6 = a(6) is the smallest integer > a(5) = 5 such that GCD(a(6),a(5)+a(4)) > 1, since GCD(6,5+3) = 2.
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MATHEMATICA
| f[l_] := Block[{k, s}, k = l[[ -1]]; s = k + l[[ -2]]; k++; While[GCD[k, s] == 1, k++ ]; Return[Append[l, k]]; ]; Nest[f, {1, 1}, 64] (*Chandler*)
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CROSSREFS
| Cf. EKG sequence A064413.
Sequence in context: A180336 A034407 A068441 * A078913 A174100 A114339
Adjacent sequences: A112595 A112596 A112597 * A112599 A112600 A112601
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KEYWORD
| easy,nonn
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AUTHOR
| Leroy Quet Dec 21 2005
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EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Dec 24 2005
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