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A154815
Period 6: repeat [8, 7, 4, 5, 2, 1].
2
8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7, 4, 5, 2, 1, 8, 7
OFFSET
0,1
COMMENTS
Obtained through reversion of the period in A153990, or by taking a half period of A154811.
Shares digits with other 6-periodic sequences, see the list in A153130.
Also the decimal expansion of the constant 97169/111111. [R. J. Mathar, Jan 23 2009]
FORMULA
a(n) = (8*A153990(n)) mod 9.
G.f.: (8+7*x+4*x^2+5*x^3+2*x^4+x^5)/((1-x)*(1+x)*(1+x+x^2)(x^2-x+1)). [R. J. Mathar, Jan 23 2009]
From Wesley Ivan Hurt, Jun 23 2016: (Start)
a(n) = a(n-6) for n>5.
a(n) = (27 + cos(n*Pi) + 8*cos(n*Pi/3) + 12*cos(2*n*Pi/3) + 8*sqrt(3)*sin(n*Pi/3) + 4*sqrt(3)*sin(2*n*Pi/3))/6. (End)
MAPLE
A154815:=n->[8, 7, 4, 5, 2, 1][(n mod 6)+1]: seq(A154815(n), n=0..100); # Wesley Ivan Hurt, Jun 23 2016
MATHEMATICA
PadRight[{}, 100, {8, 7, 4, 5, 2, 1}] (* Wesley Ivan Hurt, Jun 23 2016 *)
PROG
(Magma) &cat [[8, 7, 4, 5, 2, 1]^^20]; // Wesley Ivan Hurt, Jun 23 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Jan 15 2009
EXTENSIONS
Edited by R. J. Mathar, Jan 23 2009
STATUS
approved