%I #14 Sep 08 2022 08:45:07
%S 20,18,13,10,2,3,7,8,14,12,20,18,13,10,2,3,7,8,14,12,20,18,13,10,2,3,
%T 7,8,14,12,20,18,13,10,2,3,7,8,14,12,20,18,13,10,2,3,7,8,14,12,20,18,
%U 13,10,2,3,7,8,14,12,20,18,13,10,2,3,7,8,14,12,20,18,13,10,2
%N Every second sector of a dartboard, starting at the top (20) and working around clockwise.
%C Period 10: repeat [20,18,13,10,2,3,7,8,14,12]. - _Wesley Ivan Hurt_, Jul 15 2015
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Darts#Dartboard">Dartboard</a>
%H <a href="/index/Rec#order_10">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,0,1).
%F G.f.: x*(20+18*x+13*x^2+10*x^3+2*x^4+3*x^5+7*x^6+8*x^7+14*x^8+12*x^9) / (1-x^10). a(n) = a(n-10), n>10. - _Wesley Ivan Hurt_, Jul 15 2015
%p A076119:=n->[20,18,13,10,2,3,7,8,14,12][(n mod 10)+1]: seq(A076119(n), n=0..100); # _Wesley Ivan Hurt_, Jul 15 2015
%t CoefficientList[Series[(20 + 18 x + 13 x^2 + 10 x^3 + 2 x^4 + 3 x^5 + 7 x^6 + 8 x^7 + 14 x^8 + 12 x^9)/(1 - x^10), {x, 0, 100}], x] (* _Wesley Ivan Hurt_, Jul 15 2015 *)
%o (Magma) R:=[20,18,13,10,2,3,7,8,14,12]; [n le 10 select R[n] else Self(n-10): n in [1..100]]; // _Wesley Ivan Hurt_, Jul 15 2015
%o (Magma) &cat [[20, 18, 13, 10, 2, 3, 7, 8, 14, 12]: n in [1..7]]; // _Vincenzo Librandi_, Jul 16 2015
%o (PARI) a(n)=[12,20,18,13,10,2,3,7,8,14][n%10+1] \\ _Charles R Greathouse IV_, Aug 20 2015
%Y Cf. A003833.
%K nonn,easy
%O 1,1
%A Darren Izzard (zysyshelp(AT)yahoo.com), Oct 31 2002