login
A012772
Take every 5th term of Padovan sequence A000931, beginning with the sixth term.
2
1, 3, 12, 49, 200, 816, 3329, 13581, 55405, 226030, 922111, 3761840, 15346786, 62608681, 255418101, 1042002567, 4250949112, 17342153393, 70748973084, 288627200960, 1177482265857, 4803651498529, 19596955630177
OFFSET
0,2
FORMULA
a(n+3) = 5*a(n+2) - 4*a(n+1) + a(n).
G.f.: (1-x)^2/(1-5*x+4*x^2-x^3). - Colin Barker, Feb 02 2012
MATHEMATICA
CoefficientList[Series[(1-x)^2/(1-5*x+4*x^2-x^3), {x, 0, 33}], x] (* Vincenzo Librandi, Apr 18 2012 *)
LinearRecurrence[{5, -4, 1}, {1, 3, 12}, 30] (* Harvey P. Dale, Aug 15 2024 *)
PROG
(Magma) I:=[1, 3, 12]; [n le 3 select I[n] else 5*Self(n-1)-4*Self(n-2)+Self(n-3): n in [1..30]]; // Vincenzo Librandi, Apr 18 2012
CROSSREFS
Cf. A012781 (partial sums).
Sequence in context: A248347 A037758 A037646 * A012864 A045890 A049673
KEYWORD
nonn,easy
AUTHOR
STATUS
approved