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0, 2, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 82, 86, 90, 94, 98, 102, 106, 110, 114, 118, 122, 126, 130, 134, 138, 142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 190, 194, 198, 202, 206, 210, 214, 218, 222, 226, 230
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refs;
listen;
history;
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internal format)
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OFFSET
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0,2
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COMMENTS
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Equals A111284 from the 2nd term on. - R. J. Mathar, Jun 13 2008
Besides the first term this sequence is the denominator of (pi/8)=(1/2)-(1/6)+(1/10)-(1/14)+(1/18)-(1/22)+.... - Mohammad K. Azarian, Oct 14 2011
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REFERENCES
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Mohammad K. Azarian, Problem 1218, Pi Mu Epsilon Journal, Vol. 13, No. 2, Spring 2010, p. 116. Solution published in Vol. 13, No. 3, Fall 2010, pp. 183-185.
Granino A. Korn and Theresa M. Korn, Mathematical Handbook for Scientists and Engineers, McGraw-Hill Book Company, New York (1968).
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..10000
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FORMULA
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a(n) = 4*n-2*[(n+2) mod (n+1)], with n>=0 - Paolo P. Lava, Aug 29 2007
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MAPLE
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A130827 := proc(n) if n =0 then 0 ; else 4*n-2 ; fi ; end: seq(A130827(n), n=0..120) ; - R. J. Mathar, Oct 28 2007
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PROG
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(MAGMA) [4*n-2*Floor((n+2) mod (n+1)):n in [0..60]]; // Vincenzo Librandi, Sep 22 2011
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CROSSREFS
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Sequence in context: A187884 A068977 A111284 * A016825 A161718 A122905
Adjacent sequences: A130821 A130822 A130823 * A130825 A130826 A130827
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KEYWORD
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nonn,easy
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AUTHOR
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Paul Curtz, Jul 17 2007
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EXTENSIONS
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More terms from R. J. Mathar, Oct 28 2007
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STATUS
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approved
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