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 A011760 Elevator buttons in U.S.A.: Positive integers except 13. 4
 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Eric Weisstein's World of Mathematics, Triskaidekaphobia Wikipedia, Triskaidekaphobia Index entries for linear recurrences with constant coefficients, signature (2,-1). FORMULA a(n) = n + sign( floor( n/13 ) ). - Wesley Ivan Hurt, Jan 12 2013 G.f.: -x*(x^13-x^12-1) / (x-1)^2. - Colin Barker, May 04 2014 MATHEMATICA Drop[Range[70], {13}] (* Harvey P. Dale, Dec 11 2012 *) PROG (PARI) a(n)=if(n<13, n, n+1) \\ Charles R Greathouse IV, Sep 02 2011 CROSSREFS Cf. A085265. Cf. A076805. Sequence in context: A290492 A191431 A191430 * A085265 A180004 A252474 Adjacent sequences:  A011757 A011758 A011759 * A011761 A011762 A011763 KEYWORD nonn,nice,easy AUTHOR Juan-Carlos Lerman (jclerm(AT)aztec.asu.edu), Dec 11 1996 STATUS approved

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Last modified May 12 11:51 EDT 2021. Contains 343821 sequences. (Running on oeis4.)