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A047228 Numbers that are congruent to {2, 3, 4} mod 6. 7
2, 3, 4, 8, 9, 10, 14, 15, 16, 20, 21, 22, 26, 27, 28, 32, 33, 34, 38, 39, 40, 44, 45, 46, 50, 51, 52, 56, 57, 58, 62, 63, 64, 68, 69, 70, 74, 75, 76, 80, 81, 82, 86, 87, 88, 92, 93, 94, 98, 99, 100, 104, 105, 106, 110, 111, 112, 116, 117, 118, 122, 123, 124 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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

FORMULA

From Paul Barry, Sep 01 2009: (Start)

G.f.: (2+x+x^2+2*x^3)/(1-x-x^3+x^4).

a(n) = 2*n-1-cos(2*n*Pi/3)+sin(2*n*Pi/3)/sqrt(3). (End)

From Wesley Ivan Hurt, Jun 13 2016: (Start)

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

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

MAPLE

A047228:=n->2*n-1-cos(2*n*Pi/3)+sin(2*n*Pi/3)/sqrt(3): seq(A047228(n), n=1..100); # Wesley Ivan Hurt, Jun 13 2016

MATHEMATICA

Select[Range[0, 150], MemberQ[{2, 3, 4}, Mod[#, 6]]&] (* Vincenzo Librandi, Jan 06 2013 *)

PROG

(MAGMA) [n: n in [0..120] | n mod 6 in [2..4]]; // Vincenzo Librandi, Jan 05 2013

(Haskell)

a047228 n = a047228_list !! (n-1)

a047228_list = 2 : 3 : 4 : map (+ 6) a047228_list

-- Reinhard Zumkeller, Feb 19 2013

CROSSREFS

Cf. A007310, A047241, A047261, A047273, A097451.

Sequence in context: A230998 A184810 A246293 * A032968 A079279 A246444

Adjacent sequences:  A047225 A047226 A047227 * A047229 A047230 A047231

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

Paul Barry formula adapted for offset 1 by Wesley Ivan Hurt, Jun 13 2016

STATUS

approved

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Last modified September 18 12:45 EDT 2019. Contains 327170 sequences. (Running on oeis4.)