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Search: id:A063382
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| A063382 |
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a(1) = 5, 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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| 5, 15, 35, 57, 319, 1129, 11129, 31359, 310453, 1691837, 7241691, 15094799, 31486929, 159198031, 1159198031, 6203186877, 11721529237, 88429132553, 129487682919, 1228291054211, 1394483927247, 8800411584567, 34329256355023
(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, 5, 24 ]
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CROSSREFS
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Cf. A003681, A062094 and A062095.
Adjacent sequences: A063379 A063380 A063381 this_sequence A063383 A063384 A063385
Sequence in context: A051807 A034052 A061829 this_sequence A069983 A005894 A015622
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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 08 2001
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