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 A123932 a(0)=1, a(n)=4 for n>0. 7
 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Continued fraction for sqrt(5)-1. a(n) = number of permutations of length n+3 having only one ascent such that the first element of the permutation is 3. - Ran Pan, Apr 20 2015 Also, decimal expansion of 13/90. - Bruno Berselli, Apr 24 2015 LINKS Index entries for linear recurrences with constant coefficients, signature (1). FORMULA G.f.: (1 + 3*x) / (1 - x). a(n) = 4 - 3*0^n . a(n) = 4^n mod 12. - Zerinvary Lajos, Nov 25 2009 MATHEMATICA ContinuedFraction[Sqrt[5] - 1, 120] (* Michael De Vlieger, Apr 20 2015 *) PROG (PARI) a(n)=(n>=0)+3*(n>0) \\ Jaume Oliver Lafont, Mar 26 2009 (Sage) [power_mod(4, n, 12) for n in xrange(0, 84)] # Zerinvary Lajos, Nov 25 2009 (MAGMA) [4^n mod 12: n in [0..40]]; // Vincenzo Librandi, Apr 23 2015 (Maxima) makelist(if n=0 then 1 else 4, n, 0, 100); /* Bruno Berselli, Apr 24 2015 */ CROSSREFS Sequence in context: A088848 A088849 A251539 * A010709 A138908 A032564 Adjacent sequences:  A123929 A123930 A123931 * A123933 A123934 A123935 KEYWORD nonn,cofr,easy AUTHOR Philippe Deléham, Nov 28 2006 STATUS approved

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