OFFSET
0,2
COMMENTS
Permutation of {1,2,3,4} followed by its reversal, repeated.
Continued fraction expansion of (337 + sqrt(905669))/890 = 1.44793981253727... - R. J. Mathar, Mar 08 2012
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..8191
Index entries for linear recurrences with constant coefficients, signature (1,-1,1,-1,1,-1,1).
FORMULA
G.f.: (1 + x + 3*x^2 + 3*x^4 + x^5 + x^6)/(1 - x + x^2 - x^3 + x^4 - x^5 + x^6 - x^7). [corrected by Georg Fischer, May 15 2019]
a(n) = a(n-1) - a(n-2) + a(n-3) - a(n-4) + a(n-5) - a(n-6) + a(n-7);
a(n) = cos(3*Pi*n/4 + Pi/4)/2 + (1/2 - sqrt(2)/2)*sin(3*Pi*n/4 + Pi/4) - (1/2 + sqrt(2)/2)*cos(Pi*n/4 + Pi/4) - sin(Pi*n/4 + Pi/4)/2 - cos(Pi*n/2)/2 + sin(Pi*n/2)/2 + 5/2.
a(n) = 1 + A105198(n).
a(n) = 1 + (A000217(n) mod 4). - Jon E. Schoenfield, Aug 11 2017
MATHEMATICA
PadRight[{}, 120, {1, 2, 4, 3, 3, 4, 2, 1}] (* Harvey P. Dale, May 12 2015 *)
PROG
(PARI) a(n)=[1, 2, 4, 3, 3, 4, 2, 1][n%8+1] \\ Charles R Greathouse IV, Oct 16 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Barry, Jul 26 2005
STATUS
approved