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A166914 a(n) = 20*a(n-1) - 64*a(n-2) for n > 1; a(0) = 21, a(1) = 340. 9
21, 340, 5456, 87360, 1398016, 22369280, 357912576, 5726617600, 91625947136, 1466015416320, 23456247709696, 375299967549440, 6004799497568256, 96076792028200960, 1537228672719650816, 24595658764588154880 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Related to Reverse and Add trajectory of 318 in base 4: A075153(6*n+2) = 240*a(n).
lim_{n -> infinity} a(n)/a(n-1) = 16.
LINKS
FORMULA
a(n) = (64*16^n - 4^n)/3.
G.f.: (21 - 80*x)/((1-4*x)*(1-16*x)).
From G. C. Greubel, May 28 2016: (Start)
a(n) = 20*a(n-1) - 64*a(n-2).
E.g.f.: (1/3)*(-exp(4*x) + 64*exp(16*x)). (End)
MATHEMATICA
CoefficientList[Series[(21-80x)/((1-4x)(1-16x)), {x, 0, 20}], x] (* or *) LinearRecurrence[{20, -64}, {21, 340}, 20] (* Harvey P. Dale, Feb 23 2011 & Mar 30 2012 *)
PROG
(PARI) {m=15; v=concat([21, 340], vector(m-2)); for(n=3, m, v[n]=20*v[n-1]-64*v[n-2]); v}
CROSSREFS
Sequence in context: A113895 A062260 A278804 * A020311 A295350 A068705
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Oct 27 2009
STATUS
approved

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Last modified June 22 06:24 EDT 2024. Contains 373565 sequences. (Running on oeis4.)