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A002715
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An infinite coprime sequence defined by recursion.
(Formerly M2683 N1073)
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4
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3, 7, 23, 47, 1103, 2207, 2435423, 4870847, 11862575248703, 23725150497407, 281441383062305809756861823, 562882766124611619513723647, 158418504200047111075388369241884118003210485743490303
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| Every term is relatively prime to all others.
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REFERENCES
| A. W. F. Edwards, Infinite coprime sequences, Math. Gaz., 48 (1964), 416-422.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
| a(2n+1)=2a(2n)+1, a(2n)=(a(2n-1)^2-3)/2, a(0)=3.
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PROG
| (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
| Cf. A001685, A003686, A064526.
Sequence in context: A014426 A054270 A058000 * A112052 A205491 A203253
Adjacent sequences: A002712 A002713 A002714 * A002716 A002717 A002718
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms from J. O. Shallit.
Edited by Michael Somos Feb 01 2004
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