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Search: id:A062095
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| A062095 |
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a(1) = 1, a(n) = concatenation of two closest factors of a(n-1) whose product equals a(n-1) or if a(n-1) is a prime then the concatenation of 1 and a(n-1). |
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+0
10
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| 1, 11, 111, 337, 1337, 7191, 51141, 317047, 1317047, 2814687, 9312743, 25193697, 30981533, 51496017, 192326779, 1427134777, 4987286171, 6471777063, 61653104971, 259323776747, 737046253821, 7171027958513, 31727922601647
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(3) = 111 hence a(4) = 337, as 3*37 = 111 and 3<37.
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MATHEMATICA
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f[n_Integer] := (d = Divisors[n]; l = Length[d]; If[ EvenQ[l], ToExpression[ ToString[ d[[l/2]] ] <> ToString[ d[[l/2 + 1]] ]], ToExpression[ ToString[d[[l/2 + .5]] ] <> ToString[ d[[l/2 + .5]] ]]] ); NestList[f, 1, 25]
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CROSSREFS
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Cf. A062094, A003681.
Sequence in context: A039987 A039989 A092819 this_sequence A055657 A049121 A143573
Adjacent sequences: A062092 A062093 A062094 this_sequence A062096 A062097 A062098
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KEYWORD
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nonn,easy,base
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 16 2001
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 08 2001
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