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A047611
Numbers that are congruent to {2, 4, 5} mod 8.
1
2, 4, 5, 10, 12, 13, 18, 20, 21, 26, 28, 29, 34, 36, 37, 42, 44, 45, 50, 52, 53, 58, 60, 61, 66, 68, 69, 74, 76, 77, 82, 84, 85, 90, 92, 93, 98, 100, 101, 106, 108, 109, 114, 116, 117, 122, 124, 125, 130, 132, 133, 138, 140, 141, 146, 148, 149, 154, 156, 157
OFFSET
1,1
FORMULA
From Wesley Ivan Hurt, Jun 09 2016: (Start)
G.f.: x*(2+2*x+x^2+3*x^3)/((x-1)^2*(1+x+x^2)).
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = (24*n-15-12*cos(2*n*Pi/3)+2*sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-3, a(3k-1) = 8k-4, a(3k-2) = 8k-6. (End)
MAPLE
A047611:=n->(24*n-15-12*cos(2*n*Pi/3)+2*sqrt(3)*sin(2*n*Pi/3))/9: seq(A047611(n), n=1..100); # Wesley Ivan Hurt, Jun 09 2016
MATHEMATICA
Select[Range[0, 150], MemberQ[{2, 4, 5}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Jun 09 2016 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [2, 4, 5]]; // Wesley Ivan Hurt, Jun 09 2016
CROSSREFS
Sequence in context: A141481 A241268 A285697 * A325095 A120491 A177186
KEYWORD
nonn,easy
STATUS
approved