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A047254 Numbers that are congruent to {2, 3, 5} mod 6. 1
2, 3, 5, 8, 9, 11, 14, 15, 17, 20, 21, 23, 26, 27, 29, 32, 33, 35, 38, 39, 41, 44, 45, 47, 50, 51, 53, 56, 57, 59, 62, 63, 65, 68, 69, 71, 74, 75, 77, 80, 81, 83, 86, 87, 89, 92, 93, 95, 98, 99, 101, 104, 105, 107, 110, 111, 113, 116, 117, 119, 122, 123, 125, 128, 129 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For n>0: a(n) = greatest m<=2*(n+1) coprime to a(n-1). - Reinhard Zumkeller, Oct 31 2005

LINKS

Table of n, a(n) for n=1..65.

Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).

FORMULA

G.f.: x*(x+2)*(1+x^2) / ((1+x+x^2)*(x-1)^2). - R. J. Mathar, Oct 08 2011

From Wesley Ivan Hurt, Jun 10 2016: (Start)

a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.

a(n) = (6*n-2-cos(2*n*Pi/3)+sqrt(3)*sin(2*n*Pi/3))/3.

a(3k) = 6k-1, a(3k-1) = 6k-3, a(3k-2) = 6k-4. (End)

MAPLE

A047254:=n->(6*n-2-cos(2*n*Pi/3)+sqrt(3)*sin(2*n*Pi/3))/3: seq(A047254(n), n=1..100); # Wesley Ivan Hurt, Jun 10 2016

MATHEMATICA

Select[Range[0, 150], MemberQ[{2, 3, 5}, Mod[#, 6]] &] (* Wesley Ivan Hurt, Jun 10 2016 *)

PROG

(MAGMA) [n: n in [0..150] | n mod 6 in {2, 3, 5} ]; // Vincenzo Librandi, Dec 25 2010

CROSSREFS

Sequence in context: A027756 A119863 A285253 * A226815 A284890 A051214

Adjacent sequences:  A047251 A047252 A047253 * A047255 A047256 A047257

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified November 14 03:52 EST 2018. Contains 317159 sequences. (Running on oeis4.)