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A166927
a(n) = 20*a(n-1) - 64*a(n-2) for n > 1; a(0) = 1, a(1) = 18.
5
1, 18, 296, 4768, 76416, 1223168, 19572736, 313171968, 5010784256, 80172679168, 1282763390976, 20524216352768, 328387470032896, 5254199554080768, 84067192999510016, 1345075088529031168, 21521201418611982336
OFFSET
0,2
COMMENTS
lim_{n -> infinity} a(n)/a(n-1) = 16.
FORMULA
a(n) = (7*16^n - 4^n)/6.
G.f.: (1 - 2*x)/((1-4*x)*(1-16*x)).
E.g.f.: (1/6)*(7*exp(16*x) - exp(4*x)). - G. C. Greubel, May 28 2016
MATHEMATICA
LinearRecurrence[{20, -64}, {1, 18}, 50] (* G. C. Greubel, May 28 2016 *)
PROG
(Magma) [ n le 2 select 17*n-16 else 20*Self(n-1)-64*Self(n-2): n in [1..17] ];
CROSSREFS
Sequence in context: A048447 A167713 A219670 * A113367 A228604 A228606
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Oct 23 2009
STATUS
approved