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A047359
Numbers that are congruent to {0, 2, 3} mod 7.
1
0, 2, 3, 7, 9, 10, 14, 16, 17, 21, 23, 24, 28, 30, 31, 35, 37, 38, 42, 44, 45, 49, 51, 52, 56, 58, 59, 63, 65, 66, 70, 72, 73, 77, 79, 80, 84, 86, 87, 91, 93, 94, 98, 100, 101, 105, 107, 108, 112, 114, 115, 119, 121, 122, 126, 128, 129, 133, 135, 136, 140
OFFSET
1,2
FORMULA
G.f.: x^2*(2+x+4*x^2) / ((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-27-9*cos(2*n*Pi/3)+sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 7k-4, a(3k-1) = 7k-5, a(3k-2) = 7k-7. (End)
MAPLE
A047359:=n->(21*n-27-9*cos(2*n*Pi/3)+sqrt(3)*sin(2*n*Pi/3))/9: seq(A047359(n), n=1..100); # Wesley Ivan Hurt, Jun 08 2016
MATHEMATICA
Select[Range[0, 150], MemberQ[{0, 2, 3}, Mod[#, 7]]&] (* Harvey P. Dale, Dec 06 2012 *)
PROG
(Magma) [n : n in [0..150] | n mod 7 in [0, 2, 3]]; // Wesley Ivan Hurt, Jun 08 2016
CROSSREFS
Sequence in context: A047533 A060525 A152863 * A027700 A262300 A202105
KEYWORD
nonn,easy
STATUS
approved