OFFSET
0,2
COMMENTS
q=1 coefficient expansion of hierarchical lattice renormalization polynomial.
REFERENCES
The Beauty of Fractals, Springer-Verlag, New York, 1986, editors Peitgen and Richter, p. 146
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (6,-15,18,-9).
MAPLE
A115052 := proc(n) 1/(3*x^2-3*x+1)^2 ; coeftayl(%, x=0, n) ; end proc:# R. J. Mathar, Sep 17 2011
PROG
(Magma) I:=[1, 6, 21, 54]; [n le 4 select I[n] else 6*Self(n-1)-15*Self(n-2)+18*Self(n-3)-9*Self(n-4): n in [1..40]]; // Vincenzo Librandi, Sep 20 2011
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Roger L. Bagula, Feb 28 2006
STATUS
approved