OFFSET
0,2
COMMENTS
Sequence is identical to half its third differences.
REFERENCES
Maribel Díaz Noguera [Maribel Del Carmen Díaz Noguera], Rigoberto Flores, Jose L. Ramirez, and Martha Romero Rojas, Catalan identities for generalized Fibonacci polynomials, Fib. Q., 62:2 (2024), 100-111. See Table 3.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,3).
FORMULA
a(n) = 3*a(n-1) - 3*a(n-2) + 3*a(n-3).
O.g.f.: (1 -x +x^2)/(1 -3*x +3*x^2 -3*x^3). - R. J. Mathar, Apr 02 2008
MAPLE
m:=30; S:=series( (1-x+x^2)/(1-3*x+3*x^2-3*x^3), x, m+1):
seq(coeff(S, x, j), j=0..m); # G. C. Greubel, Apr 10 2021
MATHEMATICA
LinearRecurrence[{3, -3, 3}, {1, 2, 4}, 30] (* Ray Chandler, Sep 23 2015 *)
PROG
(Magma) I:=[1, 2, 4]; [n le 3 select I[n] else 3*(Self(n-1) -Self(n-2) +Self(n-3)): n in [1..30]]; // G. C. Greubel, Apr 10 2021
(Sage)
def A137256_list(prec):
P.<x> = PowerSeriesRing(ZZ, prec)
return P( (1-x+x^2)/(1-3*x+3*x^2-3*x^3) ).list()
A137256_list(30) # G. C. Greubel, Apr 10 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul Curtz, Mar 11 2008
EXTENSIONS
More terms from R. J. Mathar, Apr 02 2008
STATUS
approved