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A047386 Numbers that are congruent to {0, 2, 5} mod 7. 1
0, 2, 5, 7, 9, 12, 14, 16, 19, 21, 23, 26, 28, 30, 33, 35, 37, 40, 42, 44, 47, 49, 51, 54, 56, 58, 61, 63, 65, 68, 70, 72, 75, 77, 79, 82, 84, 86, 89, 91, 93, 96, 98, 100, 103, 105, 107, 110, 112, 114, 117, 119, 121, 124, 126, 128, 131, 133, 135, 138, 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

a(n+1) = 3*n-2*floor(n/3)-(n^2 mod 3). - Gary Detlefs, Mar 19 2010

G.f.: x^2*(2+3*x+2*x^2)/((1+x+x^2)*(x-1)^2). - R. J. Mathar, Dec 05 2011

From Wesley Ivan Hurt, Jun 09 2016: (Start)

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

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

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

MAPLE

seq(3*n-2*floor(n/3)-(n^2 mod 3), n=0..52); # Gary Detlefs, Mar 19 2010

MATHEMATICA

Select[Range[0, 150], MemberQ[{0, 2, 5}, Mod[#, 7]] &] (* Wesley Ivan Hurt, Jun 09 2016 *)

PROG

(MAGMA) [n : n in [0..150] | n mod 7 in [0, 2, 5]]; // Wesley Ivan Hurt, Jun 09 2016

CROSSREFS

Cf. A011655. [Gary Detlefs, Mar 19 2010]

Sequence in context: A304498 A184743 A184749 * A187416 A243808 A275278

Adjacent sequences:  A047383 A047384 A047385 * A047387 A047388 A047389

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified February 19 07:51 EST 2019. Contains 320309 sequences. (Running on oeis4.)