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A099158
a(n) = 5^(n-1) * U(n-1, 7/5) where U is the Chebyshev polynomial of the second kind.
1
0, 1, 14, 171, 2044, 24341, 289674, 3446911, 41014904, 488035881, 5807129734, 69098919251, 822206626164, 9783419785021, 116412711336194, 1385192464081191, 16482376713731824, 196123462390215761
OFFSET
0,3
FORMULA
G.f.: x/(1 - 14*x + 25*x^2).
E.g.f.: exp(7*x)*sinh(2*sqrt(6)*x)/sqrt(6).
a(n) = 14*a(n-1) - 25*a(n-2).
a(n) = sqrt(6)*(sqrt(6)+1)^(2*n)/24 - sqrt(6)*(sqrt(6)-1)^(2*n)/24.
a(n) = Sum_{k=0..n} binomial(2n, 2k+1)*6^k/2.
a(n) = 5^(n-1)*U(n-1, 7/5), where U is the Chebyshev polynomial of the second kind.
MATHEMATICA
LinearRecurrence[{14, -25}, {0, 1}, 40] (* G. C. Greubel, Jul 20 2023 *)
PROG
(PARI) a(n) = 5^(n-1)*polchebyshev(n-1, 2, 7/5); \\ Michel Marcus, Sep 08 2019
(Magma) [n le 2 select n-1 else 14*Self(n-1) -25*Self(n-2): n in [1..30]]; // G. C. Greubel, Jul 20 2023
(SageMath)
A099158=BinaryRecurrenceSequence(14, -25, 0, 1)
[A099158(n) for n in range(41)] # G. C. Greubel, Jul 20 2023
CROSSREFS
Sequence in context: A098299 A341500 A254811 * A014882 A048443 A191690
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Oct 01 2004
STATUS
approved