OFFSET
0,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,-8).
FORMULA
G.f.: x/(1 - 4*x + 8*x^2). - Philippe Deléham, Oct 12 2011
a(n) = 2^(n-1)*A009545(n). - R. J. Mathar, Apr 07 2022
From G. C. Greubel, Jan 10 2024: (Start)
a(n) = 8^((n-1)/2)*ChebyshevU(n-1, 1/sqrt(2)).
E.g.f.: (1/2)*exp(2*x)*sin(2*x). (End)
MATHEMATICA
LinearRecurrence[{4, -8}, {0, 1}, 50]
PROG
(Magma) [n le 2 select n-1 else 4*(Self(n-1) -2*Self(n-2)): n in [1..41]]; // G. C. Greubel, Jan 10 2024
(SageMath)
A190966=BinaryRecurrenceSequence(4, -8, 0, 1)
[A190966(n) for n in range(41)] # G. C. Greubel, Jan 10 2024
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Vladimir Joseph Stephan Orlovsky, May 24 2011
STATUS
approved