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A139047
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a(0)=a(1)=1. For n >= 2, if a(n-1) is coprime to n, then a(n) = a(n-1) + a(n-2). Otherwise, a(n)=1.
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2
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1, 1, 2, 3, 5, 1, 6, 7, 13, 20, 1, 21, 1, 22, 1, 23, 24, 47, 71, 118, 1, 119, 120, 239, 359, 598, 1, 599, 600, 1199, 1799, 2998, 1, 2999, 3000, 1, 3001, 3002, 1, 3003, 3004, 6007, 9011, 15018, 1, 15019, 1, 15020, 1, 15021, 15022, 30043, 1, 30044, 1, 30045, 30046, 60091
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OFFSET
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0,3
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LINKS
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EXAMPLE
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16 is coprime to a(15) = 23, so a(16) = a(15) + a(14) = 23 + 1 = 24.
20 is not coprime to a(19) = 118, so a(20) = 1.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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More terms from Jasper Mulder (jasper.mulder(AT)planet.nl), Oct 12 2009
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STATUS
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approved
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