OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..950
Index entries for linear recurrences with constant coefficients, signature (19,-116,284,-240).
FORMULA
a(n) = 19*a(n-1) - 116*a(n-2) + 284*a(n-3) - 240*a(n-4), with a(0)=1, a(1)=19, a(2)=245, a(3)=2735. - Harvey P. Dale, Oct 18 2011
a(n) = (10^(n+3) - 7*4^(n+4) + 16*3^(n+4) - 21*2^(n+3))/336. - Yahia Kahloune, May 19 2013
a(n) = 3^(n+1) - 2^(n+1) + 14*a(n-1) - 40*a(n-2). - Vincenzo Librandi, Apr 15 2026
MATHEMATICA
CoefficientList[Series[1/((1-2x)(1-3x)(1-4x)(1-10x)), {x, 0, 30}], x] (* or *) LinearRecurrence[{19, -116, 284, -240}, {1, 19, 245, 2735}, 31] (* Harvey P. Dale, Oct 18 2011 *)
a[0]=1; a[1]=19; a[n_]:=a[n]=3^(n+1)-2^(n+1)+14 a[n-1]-40 a[n-2]; Table[a[n], {n, 0, 20}] (* Vincenzo Librandi, Apr 15 2026 *)
PROG
(PARI) Vec((-4560*x^3 + 5156*x^2 - 1920*x + 245)/(240*x^4 - 284*x^3 + 116*x^2 - 19*x + 1)+O(x^25)) \\ Charles R Greathouse IV, May 20 2013
(Magma) I:=[1, 19]; [n le 2 select I[n] else 3^n - 2^n + 14*Self(n-1)-40*Self(n-2): n in [1..25]]; // Vincenzo Librandi, Apr 15 2026
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Apr 15 2026
STATUS
approved
