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A002716
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An infinite coprime sequence defined by recursion.
(Formerly M2488 N0986)
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1
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3, 5, 13, 17, 241, 257, 65281, 65537, 4294901761, 4294967297, 18446744069414584321, 18446744073709551617, 340282366920938463444927863358058659841
(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)=a(2n)+a(2n-1)-1, a(2n)=a(2n-1)^2-3*a(2n-1)+3, a(0)=3, a(1)=5.
Conjecture: a(2n+1)=A001146(n+1)+1. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 15 2007
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PROG
| (PARI) a(n)=if(n<2, 3*(n>=0)+2*(n>0), if(n%2, a(n-1)+a(n-2)-1, a(n-1)^2-3*a(n-1)+3))
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CROSSREFS
| Cf. A001685, A002715, A003686, A064526.
Sequence in context: A038185 A131020 A084706 * A046154 A180120 A075704
Adjacent sequences: A002713 A002714 A002715 * A002717 A002718 A002719
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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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