VOOZH about

URL: https://oeis.org/A047440

⇱ A047440 - OEIS

login
A047440
Numbers that are congruent to {2, 5, 6} mod 8.
1
2, 5, 6, 10, 13, 14, 18, 21, 22, 26, 29, 30, 34, 37, 38, 42, 45, 46, 50, 53, 54, 58, 61, 62, 66, 69, 70, 74, 77, 78, 82, 85, 86, 90, 93, 94, 98, 101, 102, 106, 109, 110, 114, 117, 118, 122, 125, 126, 130, 133, 134, 138, 141, 142, 146, 149, 150, 154, 157, 158
OFFSET
1,1
FORMULA
G.f.: x*(2+3*x+x^2+2*x^3)/((1+x+x^2)*(x-1)^2). - R. J. Mathar, Dec 07 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) = (24*n-9-9*cos(2*n*Pi/3)-sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-2, a(3k-1) = 8k-3, a(3k-2) = 8k-6. (End)
MAPLE
A047440:=n->(24*n-9-9*cos(2*n*Pi/3)-sqrt(3)*sin(2*n*Pi/3))/9: seq(A047440(n), n=1..100); # Wesley Ivan Hurt, Jun 09 2016
MATHEMATICA
Flatten[{#+2, #+5, #+6}&/@(8 Range[0, 20])] (* Harvey P. Dale, Dec 19 2010 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [2, 5, 6]]; // Wesley Ivan Hurt, Jun 09 2016
(PARI) isok(n) = my (m=n%8); m==2 || m==5 || m==6; \\ Bruce Nye, Apr 03 2026
CROSSREFS
Sequence in context: A212015 A255341 A089269 * A255055 A344314 A369020
KEYWORD
nonn,easy,changed
STATUS
approved