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A166965 a(n) = 20*a(n-1) - 64*a(n-2) for n > 1; a(0) = 1, a(1) = 19. 5
1, 19, 316, 5104, 81856, 1310464, 20970496, 335540224, 5368692736, 85899280384, 1374389272576, 21990231506944, 351843716694016, 5629499517435904, 90071992480301056, 1441151880490123264, 23058430091063197696 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
lim_{n -> infinity} a(n)/a(n-1) = 16.
LINKS
FORMULA
a(n) = (5*16^n - 4^n)/4.
G.f.: (1-x)/((1-4*x)*(1-16*x)).
E.g.f.: (1/4)*(5*exp(16*x) - exp(4*x)). - G. C. Greubel, May 29 2016
MATHEMATICA
LinearRecurrence[{20, -64}, {1, 19}, 20] (* Harvey P. Dale, Aug 24 2014 *)
PROG
(Magma) [ n le 2 select 18*n-17 else 20*Self(n-1)-64*Self(n-2): n in [1..17] ];
CROSSREFS
Cf. A166927, A006105 (Gaussian binomial coefficient [ n, 2 ] for q=4).
Sequence in context: A180845 A138943 A111420 * A372193 A137352 A027541
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Oct 25 2009
STATUS
approved

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Last modified May 21 19:35 EDT 2024. Contains 372738 sequences. (Running on oeis4.)