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Search: id:A063403
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| A063403 |
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a(1) = 8, 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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1
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| 8, 24, 46, 223, 1223, 11223, 87129, 189461, 414621, 2072003, 12072003, 34024001, 163920759, 354640253, 1074732999, 7377145687, 17377145687, 57053304579, 393145173803, 834736688841, 8062231035367, 26899299722333, 27745499695017
(list; graph; listen)
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OFFSET
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1,1
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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, 8, 25 ]
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CROSSREFS
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Cf. A003681, A062094 and A062095.
Sequence in context: A031046 A051062 A074348 this_sequence A122812 A022763 A033996
Adjacent sequences: A063400 A063401 A063402 this_sequence A063404 A063405 A063406
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KEYWORD
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base,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 09 2001
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