A047277 Numbers that are congruent to {0, 2, 6} mod 7.

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

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 A358579 A341437

Adjacent sequences: A047274 A047275 A047276 * A047278 A047279 A047280

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved