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A047375 Numbers that are congruent to {0, 4, 5} mod 7. 1
0, 4, 5, 7, 11, 12, 14, 18, 19, 21, 25, 26, 28, 32, 33, 35, 39, 40, 42, 46, 47, 49, 53, 54, 56, 60, 61, 63, 67, 68, 70, 74, 75, 77, 81, 82, 84, 88, 89, 91, 95, 96, 98, 102, 103, 105, 109, 110, 112, 116, 117, 119, 123, 124, 126, 130, 131, 133, 137, 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

G.f.: x^2*(4+x+2*x^2) / ((1+x+x^2)*(x-1)^2). - R. J. Mathar, Dec 04 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-15-3*cos(2*n*Pi/3)-5*sqrt(3)*sin(2*n*Pi/3))/9.

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

MAPLE

A047375:=n->(21*n-15-3*cos(2*n*Pi/3)-5*sqrt(3)*sin(2*n*Pi/3))/9: seq(A047375(n), n=1..100); # Wesley Ivan Hurt, Jun 09 2016

MATHEMATICA

Select[Range[0, 150], MemberQ[{0, 4, 5}, Mod[#, 7]] &] (* Wesley Ivan Hurt, Jun 09 2016 *)

PROG

(MAGMA) [n : n in [0..150] | n mod 7 in [0, 4, 5]]; // Wesley Ivan Hurt, Jun 09 2016

CROSSREFS

Sequence in context: A057708 A032686 A074300 * A005487 A291741 A084087

Adjacent sequences:  A047372 A047373 A047374 * A047376 A047377 A047378

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified January 28 00:32 EST 2020. Contains 331313 sequences. (Running on oeis4.)