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A047277 Numbers that are congruent to {0, 2, 6} mod 7. 1
0, 2, 6, 7, 9, 13, 14, 16, 20, 21, 23, 27, 28, 30, 34, 35, 37, 41, 42, 44, 48, 49, 51, 55, 56, 58, 62, 63, 65, 69, 70, 72, 76, 77, 79, 83, 84, 86, 90, 91, 93, 97, 98, 100, 104, 105, 107, 111, 112, 114, 118, 119, 121, 125, 126, 128, 132, 133, 135, 139, 140 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..61.

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

FORMULA

G.f.: x^2*(2+4*x+x^2) / ((1+x+x^2)*(x-1)^2). - R. J. Mathar, Oct 25 2011

From Wesley Ivan Hurt, Jun 07 2016: (Start)

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

a(n) = 7*n/3-2+cos(2*n*Pi/3)+sin(2*n*Pi/3)/(3*sqrt(3)).

a(3k) = 7k-1, a(3k-1) = 7k-5, a(3k-2) = 7k-7. (End)

MAPLE

A047277:=n->7*n/3-2+cos(2*n*Pi/3)+sin(2*n*Pi/3)/(3*sqrt(3)): seq(A047277(n), n=1..100); # Wesley Ivan Hurt, Jun 07 2016

MATHEMATICA

Table[7*n/3-2+Cos[2*n*Pi/3]+Sin[2*n*Pi/3]/(3*Sqrt[3]), {n, 80}] (* Wesley Ivan Hurt, Jun 07 2016 *)

PROG

(MAGMA) [n : n in [0..150] | n mod 7 in [0, 2, 6]]; // Wesley Ivan Hurt, Jun 07 2016

CROSSREFS

Sequence in context: A020898 A184779 A200926 * A308198 A327985 A189465

Adjacent sequences:  A047274 A047275 A047276 * A047278 A047279 A047280

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified October 19 21:08 EDT 2019. Contains 328228 sequences. (Running on oeis4.)