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A047228
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Numbers that are congruent to {2, 3, 4} mod 6.
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7
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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
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refs;
listen;
history;
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internal format)
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OFFSET
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1,1
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).
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FORMULA
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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)
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MAPLE
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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
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MATHEMATICA
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Select[Range[0, 150], MemberQ[{2, 3, 4}, Mod[#, 6]]&] (* Vincenzo Librandi, Jan 06 2013 *)
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PROG
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(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
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CROSSREFS
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Cf. A007310, A047241, A047261, A047273, A097451.
Sequence in context: A230998 A184810 A246293 * A032968 A079279 A246444
Adjacent sequences: A047225 A047226 A047227 * A047229 A047230 A047231
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane
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EXTENSIONS
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Paul Barry formula adapted for offset 1 by Wesley Ivan Hurt, Jun 13 2016
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STATUS
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approved
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