OFFSET
1,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (20, -115, 240,-144).
FORMULA
G.f.: (-360x^2 + 96x) / (-144x^4 + 240x^3 - 115x^2 + 20x - 1).
G.f.: 24*x*(4 - 15*x)/((1 - x)*(1 - 3*x)*(1 - 4*x)*(1 - 12*x)). - Andrew Howroyd, Jul 04 2018
a(n) = 20*a(n-1) - 115*a(n-2) + 240*a(n-3) - 144*a(n-4). - Vincenzo Librandi, Jul 04 2018
MATHEMATICA
LinearRecurrence[{20, -115, 240, -144}, {0, 96, 1560, 20160}, 40] (* Vincenzo Librandi, Jul 04 2018 *)
PROG
(PARI) concat([0], Vec(24*(4 - 15*x)/((1 - x)*(1 - 3*x)*(1 - 4*x)*(1 - 12*x)) + O(x^20))) \\ Andrew Howroyd, Jul 04 2018
(Magma) I:=[0, 96, 1560, 20160]; [n le 4 select I[n] else 20*Self(n-1)- 115*Self(n-2)+240*Self(n-3)-144*Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jul 04 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Sharon Sela (sharonsela(AT)hotmail.com), Jun 04 2002
EXTENSIONS
Terms a(10) and beyond from Andrew Howroyd, Jul 04 2018
STATUS
approved