A011760 Elevator buttons in U.S.A.: Positive integers except 13.

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

Offset: 1

Author

Juan-Carlos Lerman (jclerm(AT)aztec.asu.edu), Dec 11 1996

Keywords

• nonn
• nice
• easy

Links

• Eric Weisstein's World of Mathematics, Triskaidekaphobia
• Wikipedia, Triskaidekaphobia
• Index entries for linear recurrences with constant coefficients, signature (2,-1).

Crossrefs

Cf. A085265.

Cf. A076805.

Programs

Mathematica

Drop[Range[70],{13}] (* Harvey P. Dale, Dec 11 2012 *)

PARI

a(n)=if(n<13,n,n+1) \\ Charles R Greathouse IV, Sep 02 2011

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