cp's OEIS Frontend

A247525 a(n) = 5 * a(n-1) - 2 * a(n-1)^2 / a(n-2), with a(0) = 1, a(1) = 2.

%I A247525 #8 Sep 08 2022 08:46:09
%S A247525 1,2,2,6,-6,-42,378,8694,-356454,-31011498,5240943162,1797643504566,
%T A247525 -1224195226609446,-1673474874775112682,4566912933261282509178,
%U A247525 24949045354406386347639414,-272468524315472145302570040294,-5952619850720119958425247670303018
%N A247525 a(n) = 5 * a(n-1) - 2 * a(n-1)^2 / a(n-2), with a(0) = 1, a(1) = 2.
%H A247525 G. C. Greubel, <a href="/A247525/b247525.txt">Table of n, a(n) for n = 0..83</a>
%F A247525 0 = a(n)*(-5*a(n+1) + a(n+2)) + a(n+1)*(+2*a(n+1)) for all n in Z.
%F A247525 a(n+1) = a(n) * A140966(n) for all n in Z.
%t A247525 RecurrenceTable[{a[n] == 5*a[n - 1] - 2*a[n - 1]^2/a[n - 2], a[0] == 1, a[1] == 2}, a, {n, 0, 50}] (* _G. C. Greubel_, Aug 05 2018 *)
%o A247525 (PARI) {a(n) = if( n<0, 1 / prod(k=1, -n, (5 + (-2)^-k) / 3), prod(k=0, n-1, (5 + (-2)^k) / 3))};
%o A247525 (Magma) I:=[1, 2]; [n le 2 select I[n] else 5*Self(n-1) - 2*Self(n-1)^2/Self(n-2): n in [1..30]]; // _G. C. Greubel_, Aug 05 2018
%Y A247525 Cf. A140966.
%K A247525 sign
%O A247525 0,2
%A A247525 _Michael Somos_, Sep 18 2014