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A047339 Numbers that are congruent to {2, 3, 4} mod 7. 1
2, 3, 4, 9, 10, 11, 16, 17, 18, 23, 24, 25, 30, 31, 32, 37, 38, 39, 44, 45, 46, 51, 52, 53, 58, 59, 60, 65, 66, 67, 72, 73, 74, 79, 80, 81, 86, 87, 88, 93, 94, 95, 100, 101, 102, 107, 108, 109, 114, 115, 116, 121, 122, 123, 128, 129, 130, 135, 136, 137, 142 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..3000

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

FORMULA

a(n+1) = 7*floor(n/3)+(n mod 3)+2. - Gary Detlefs, Mar 09 2010

G.f.: x*(2+x+x^2+3*x^3)/((1+x+x^2)*(x-1)^2). - R. J. Mathar, Dec 04 2011

From Wesley Ivan Hurt, Jun 08 2016: (Start)

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

a(n) = (21*n-15-12*cos(2*n*Pi/3)+4*sqrt(3)*sin(2*n*Pi/3))/9.

a(3k) = 7k-3, a(3k-1) = 7k-4, a(3k-2) = 7k-5. (End)

MAPLE

seq(7*floor(n/3)+(n mod 3)+2, n= 0..52); # Gary Detlefs, Mar 09 2010

MATHEMATICA

Select[Range[0, 150], MemberQ[{2, 3, 4}, Mod[#, 7]] &] (* Wesley Ivan Hurt, Jun 08 2016 *)

PROG

(MAGMA) [n : n in [0..150] | n mod 7 in [2..4]]; // Wesley Ivan Hurt, Jun 08 2016

CROSSREFS

Sequence in context: A165315 A284681 A309346 * A250483 A294485 A084368

Adjacent sequences:  A047336 A047337 A047338 * A047340 A047341 A047342

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified October 16 03:37 EDT 2019. Contains 328040 sequences. (Running on oeis4.)