
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
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..68.
Eric Weisstein's World of Mathematics, Triskaidekaphobia
Wikipedia, Triskaidekaphobia
Index to sequences with 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^13x^121) / (x1)^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: A161951 A191431 A191430 * A085265 A180004 A172270
Adjacent sequences: A011757 A011758 A011759 * A011761 A011762 A011763


KEYWORD

nonn,nice,easy


AUTHOR

JuanCarlos Lerman (jclerm(AT)aztec.asu.edu), Dec 11 1996


STATUS

approved

