OFFSET
1,1
COMMENTS
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).
G.f.: x*(-89-3631*x-1898*x^2)/(x-1)^3.
MATHEMATICA
LinearRecurrence[{3, -3, 1}, {89, 3898, 13325}, 40]
Table[2809n^2-4618n+1898, {n, 40}] (* Harvey P. Dale, Aug 02 2024 *)
PROG
(Magma) I:=[89, 3898, 13325]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]];
(PARI) a(n) = 2809*n^2 - 4618*n + 1898;
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Mar 06 2009
STATUS
approved