OFFSET
0,2
COMMENTS
Cell configuration converges to a fractal with dimension 2.906...
LINKS
Colin Barker, Table of n, a(n) for n = 0..700
Peter Karpov, InvMem, Item 26
Index entries for linear recurrences with constant coefficients, signature (32,-195,216).
FORMULA
a(0) = 1, a(1) = 26, a(2) = 646, a(n) = 28*a(n-1) - 195*a(n-2) + 216*a(n-3).
G.f.: (1-6*x+9*x^2)/(1-32*x+195*x^2-216*x^3).
MATHEMATICA
LinearRecurrence[{32, -195, 216}, {1, 26, 646}, 18]
PROG
(PARI) Vec((1 - 3*x)^2 / (1 - 32*x + 195*x^2 - 216*x^3) + O(x^20)) \\ Colin Barker, Apr 23 2017
(Sage)
def A285397_list(prec):
P.<x> = PowerSeriesRing(ZZ, prec)
return P( (1-6*x+9*x^2)/(1-32*x+195*x^2-216*x^3) ).list()
A285397_list(40) # G. C. Greubel, Dec 09 2021
(Magma)
I:=[1, 26, 646]; [n le 3 select I[n] else 32*Self(n-1) - 195*Self(n-2) + 216*Self(n-3) : n in [1..41]]; // G. C. Greubel, Dec 09 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Peter Karpov, Apr 23 2017
STATUS
approved