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Search: id:A144751
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| A144751 |
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a(1) = 3, a(n + 1) = 1 + a(n) + least odd prime factor of a(n). |
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+0
2
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| 3, 7, 15, 19, 39, 43, 87, 91, 99, 103, 207, 211, 423, 427, 435, 439, 879, 883, 1767, 1771, 1779, 1783, 3567, 3571, 7143, 7147, 7155, 7159, 14319, 14323, 28647, 28651, 28659, 28663, 57327, 57331, 114663, 114667, 114675, 114679, 229359
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OFFSET
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1,1
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COMMENT
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The conjectured g.f. (-4*x^11 + 12*x^10 + 8*x^9 + 24*x^8 + 56*x^7 + 72*x^6 + 43*x^5 + 39*x^4 + 19*x^3 + 15*x^2 + 7*x + 3)/(4*x^12 - 5*x^6 + 1) is wrong; it matches only the first 41 terms of the sequence [R. J. Mathar, mathar(AT)strw.leidenuniv.nl), Jun 16 2009]
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MATHEMATICA
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vec=NestList[ #+1+Cases[ FactorInteger[ # ][ [ All, 1 ] ], _?OddQ, 1, 1 ][ [ 1 ] ]&, 3, 100 ]
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CROSSREFS
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Equals A140525 + 1.
Sequence in context: A111294 A092899 A075694 this_sequence A138847 A077777 A153829
Adjacent sequences: A144748 A144749 A144750 this_sequence A144752 A144753 A144754
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KEYWORD
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nonn
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AUTHOR
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Peter Pein, Feb 09 2009
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