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Search: id:A002715
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| A002715 |
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An infinite coprime sequence defined by recursion.
(Formerly M2683 N1073)
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+0
5
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| 3, 7, 23, 47, 1103, 2207, 2435423, 4870847, 11862575248703, 23725150497407, 281441383062305809756861823, 562882766124611619513723647, 158418504200047111075388369241884118003210485743490303
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Every term is relatively prime to all others.
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
A. W. F. Edwards, Infinite coprime sequences, Math. Gaz., 48 (1964), 416-422.
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FORMULA
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a(2n+1)=2a(2n)+1, a(2n)=(a(2n-1)^2-3)/2, a(0)=3.
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PROGRAM
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(PARI) a(n)=if(n<1, 3*(n==0), if(n%2, 2*a(n-1)+1, (a(n-1)^2-3)/2))
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CROSSREFS
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Cf. A001685, A003686, A064526.
Sequence in context: A014426 A054270 A058000 this_sequence A112052 A127178 A058757
Adjacent sequences: A002712 A002713 A002714 this_sequence A002716 A002717 A002718
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from J. O. Shallit.
Edited by Michael Somos Feb 01 2004
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