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A074693
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a(1) = 1, a(n) = a(n-1) + phi(a(n-1)).
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3
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1, 2, 3, 5, 9, 15, 23, 45, 69, 113, 225, 345, 521, 1041, 1733, 3465, 4905, 7497, 11529, 18009, 29097, 47817, 71577, 114777, 184761, 307881, 482841, 804573, 1212813, 1854333, 2993517, 4953069, 7752429, 12826269, 21376953, 34207353, 55027593, 91712493, 152705493
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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1 < a(n+1)/a(n) <= 2 . Does limit a(n+1)/a(n) exist ?
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MAPLE
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a:= proc(n) option remember; `if`(n=1, 1,
numtheory[phi](a(n-1))+a(n-1))
end:
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MATHEMATICA
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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