A047349 Numbers that are congruent to {0, 2, 4} mod 7.

0, 2, 4, 7, 9, 11, 14, 16, 18, 21, 23, 25, 28, 30, 32, 35, 37, 39, 42, 44, 46, 49, 51, 53, 56, 58, 60, 63, 65, 67, 70, 72, 74, 77, 79, 81, 84, 86, 88, 91, 93, 95, 98, 100, 102, 105, 107, 109, 112, 114, 116, 119, 121, 123, 126, 128, 130, 133, 135, 137, 140, 142

Offset

1,2

Links

Table of n, a(n) for n=1..62.

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

Formula

a(n+1) = floor(n/3)+2*n. - Gary Detlefs, Mar 27 2010

G.f.: x^2*(2+2*x+3*x^2)/((1+x+x^2)*(x-1)^2). - R. J. Mathar, Oct 08 2011

a(n) = n + floor(4*(n-1)/3) - 1. - Arkadiusz Wesolowski, Sep 18 2012

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

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

a(n) = (21*n-24-3*cos(2*n*Pi/3)+sqrt(3)*sin(2*n*Pi/3))/9.

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

Maple

seq(floor(n/3)+2*n, n=0..52); # Gary Detlefs, Mar 27 2010

Mathematica

Select[Range[0, 150], MemberQ[{0, 2, 4}, Mod[#, 7]] &] (* Wesley Ivan Hurt, Jun 10 2016 *)

Prog

(Magma) [n : n in [0..150] | n mod 7 in [0, 2, 4]]; // Wesley Ivan Hurt, Jun 10 2016

Crossrefs

Sequence in context: A111495 A187686 A024812 * A329842 A054406 A292647

Adjacent sequences: A047346 A047347 A047348 * A047350 A047351 A047352

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved