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Search: id:A112598
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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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1
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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; listen)
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OFFSET
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1,3
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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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For n >= 9, a(n) = 2n.
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EXAMPLE
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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
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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
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Cf. EKG sequence A064413.
Sequence in context: A039896 A034407 A068441 this_sequence A078913 A114339 A127525
Adjacent sequences: A112595 A112596 A112597 this_sequence A112599 A112600 A112601
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KEYWORD
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easy,nonn
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AUTHOR
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Leroy Quet Dec 21 2005
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Dec 24 2005
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