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 A060747 a(n) = 2*n - 1. 21
 -1, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS If you put n red balls and n blue balls in a bag and draw them one by one without replacement, the probability of never having drawn equal numbers of the two colors before the final ball is drawn is 1/a(n) unsigned. abs(a(n)) = 2n - 1 + 2*0^n. It has A048495 as binomial transform. - Paul Barry, Jun 09 2003 For n >= 1, a(n) = numbers k such that arithmetic mean of the first k positive integers is integer. A040001(a(n)) = 1. See A145051 and A040001. -  Jaroslav Krizek, May 28 2010 From Jaroslav Krizek, May 28 2010: (Start) For n >= 1, a(n) = corresponding values of antiharmonic means to numbers from A016777 (numbers k such that antiharmonic mean of the first k positive integers is integer). a(n) = A000330(A016777(n)) / A000217(A016777(n)) = A146535(A016777(n)+1). (End) LINKS Tanya Khovanova, Recursive Sequences Index entries for linear recurrences with constant coefficients, signature (2,-1). FORMULA a(n) = A005408(n)-2 = A005843(n)-1 = -A000984(n)/A002420(n) = A001477(n)+A023443(n). G.f.: (3*x - 1)/(1 - x)^2. Abs(a(n)) = Sum_{k=0..n} (A078008(k) mod 4). - Paul Barry, Mar 12 2004 E.g.f.: exp(x)*(2*x-1). - Paul Barry, Mar 31 2007 a(n) = 2*a(n-1) - a(n-2); a(0)=-1, a(1)=1. - Philippe Deléham, Nov 03 2008 a(n) = 4*n - a(n-1) - 4 for n>0, with a(0)=-1. - Vincenzo Librandi, Aug 07 2010 MATHEMATICA Table[2*n - 1, {n, 0, 200}] (* Vladimir Joseph Stephan Orlovsky, Feb 16 2012 *) LinearRecurrence[{2, -1}, {-1, 1}, 80] (* Harvey P. Dale, Mar 27 2020 *) PROG (Haskell) a060747 = subtract 1 . (* 2) a060747_list = [-1, 1 ..] -- Reinhard Zumkeller, Jul 05 2015 -- Reinhard Zumkeller, Jul 05 2015 (PARI) a(n)=2*n-1 \\ Charles R Greathouse IV, Sep 24 2015 CROSSREFS Sequence in context: A005408 A176271 A144396 * A089684 A283002 A105356 Adjacent sequences:  A060744 A060745 A060746 * A060748 A060749 A060750 KEYWORD sign,easy AUTHOR Henry Bottomley, Apr 26 2001 STATUS approved

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Last modified October 29 03:28 EDT 2020. Contains 338065 sequences. (Running on oeis4.)