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Search: id:A139759
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| A139759 |
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A Fibonacci based recurrence. |
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+0
1
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| 1, 1, 2, 3, 4, 7, 10, 11, 20, 31, 42, 73, 110, 183, 292, 473, 762, 1235, 1992, 3209, 5198, 8407, 13604, 22011, 35614, 57625, 93238, 150863, 244100, 394963, 639054, 1034017, 1673070, 2707089, 4380158, 7087241, 11467398, 18554639, 30022036, 48576675
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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E. S. Rowland, A natural prime-generating recurrence, arXiv:0710.3217 [math.NT]
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FORMULA
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a(n)=a(n-1)+a(n-2)+gcd(n,a(n-1))-gcd(n,a(n-2))
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MAPLE
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A139759 := proc(n) option remember ; if n <= 1 then 1; else an_1 := A139759(n-1) ; an_2 := A139759(n-2) ; an_1+an_2+gcd(n, an_1)-gcd(n, an_2) ; fi ; end: seq(A139759(n), n=0..60) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 20 2008
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CROSSREFS
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Cf. A000045.
Sequence in context: A080724 A089589 A047546 this_sequence A030292 A135419 A051914
Adjacent sequences: A139756 A139757 A139758 this_sequence A139760 A139761 A139762
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KEYWORD
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easy,nonn
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AUTHOR
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Ctibor O. Zizka (ctibor.zizka(AT)seznam.cz), May 20 2008
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 20 2008
Converted reference to link - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 30 2009
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