OFFSET
0,2
COMMENTS
lim_{n -> infinity} a(n)/a(n-1) = 16.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (21,-84,64).
FORMULA
a(n) = (4337*16^n - 1540*4^n + 128)/2880, for n > 0.
G.f.: (1 + x - x^2 + x^3)/((1-x)*(1-4*x)*(1-16*x)).
E.g.f.: (1/2880)*(-45 + 128*exp(x) - 1540*exp(4*x) + 4337*exp(16*x)). - G. C. Greubel, Jun 04 2016
MATHEMATICA
CoefficientList[Series[(1 + x - x^2 + x^3)/((1-x)*(1-4*x)*(1-16*x)), {x, 0, 10}], x] (* G. C. Greubel, Jun 04 2016 *)
Join[{1}, RecurrenceTable[{a[1]==22, a[2]==377, a[n]==20a[n-1]-64a[n-2]+2}, a, {n, 20}]] (* Harvey P. Dale, Apr 01 2019 *)
PROG
(Magma) [ n le 2 select 21*n-20 else n eq 3 select 377 else 20*Self(n-1)-64*Self(n-2)+2: n in [1..17] ];
CROSSREFS
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Oct 27 2009
STATUS
approved