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A047349 Numbers that are congruent to {0, 2, 4} mod 7. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 11 00:32 EDT 2020. Contains 336403 sequences. (Running on oeis4.)