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%I #27 Jan 05 2023 18:40:38
%S 0,1,2,4,9,26,108,785,12450,628676,155631177,395389144154,
%T 24221458643549484,156332599536291235925201,
%U 586679058977510608947573592591458,24439881677774993432884951095586547256059481860
%N a(n) = a(n-2)^2 + a(n-1) + 1 for n >= 2 with a(0) = 0 and a(1) = 1.
%t a[0] = 0; a[1] = 1; a[n_] := a[n] = a[n - 2]^2 + a[n - 1] + 1; Array[a, 16, 0] (* _Amiram Eldar_, Jan 05 2023 *)
%o (Python)
%o # a generator
%o def agen_q():
%o a, b = 0, 1
%o while 1:
%o yield a
%o a, b = b, (a * a) + b + 1
%o f = agen_q(); print([next(f) for _ in range(20)])
%Y Cf. A000278, A000283.
%K nonn
%O 0,3
%A _Andrew Wall_, Jan 03 2023
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