OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (4,0,1,-4).
FORMULA
a(n) = +4*a(n-1) +a(n-3) -4*a(n-4). G.f.: x / ( (x-1)*(4*x-1)*(1+x+x^2) ). - R. J. Mathar, Jan 08 2011
MATHEMATICA
LinearRecurrence[{4, 0, 1, -4}, {1, 4, 16, 65}, 30] (* Vincenzo Librandi, Jun 21 2012 *)
Table[FromDigits[PadRight[{}, n, {1, 0, 0}], 4], {n, 30}] (* Harvey P. Dale, Apr 15 2018 *)
PROG
(Magma) I:=[1, 4, 16, 65]; [n le 4 select I[n] else 4*Self(n-1)+Self(n-3)-4*Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jun 21 2012
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
STATUS
approved