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 A130824 a(n) = 2*A004273(n). 2
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS 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 REFERENCES 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). LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..10000 FORMULA a(n) = 4*n-2*[(n+2) mod (n+1)], with n>=0 - Paolo P. Lava, Aug 29 2007 MAPLE 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 PROG (MAGMA) [4*n-2*Floor((n+2) mod (n+1)):n in [0..60]]; // Vincenzo Librandi, Sep 22 2011 CROSSREFS Sequence in context: A187884 A068977 A111284 * A016825 A161718 A122905 Adjacent sequences:  A130821 A130822 A130823 * A130825 A130826 A130827 KEYWORD nonn,easy AUTHOR Paul Curtz, Jul 17 2007 EXTENSIONS More terms from R. J. Mathar, Oct 28 2007 STATUS approved

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Last modified June 19 19:50 EDT 2013. Contains 226416 sequences.