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%I #27 Mar 13 2019 14:55:45
%S 1,1,1,2,2,5,34,582076609134674072265627
%N a(0)=1, a(1)=1, a(2)=1; thereafter a(n)=a(n-2)^a(n-1)+a(n-3).
%C a(8) has approximately 2.1*10^18 digits.
%t nxt[{a_,b_,c_}]:={b,c,b^c+a}; NestList[nxt,{1,1,1},7][[All,1]]//Quiet (* _Harvey P. Dale_, Mar 13 2019 *)
%o (Maxima)
%o a[0]:1$
%o a[1]:1$
%o a[2]:1$
%o a[n]:=a[n-2]^a[n-1]+a[n-3]$
%o makelist(a[n],n,0,7); /* _Martin Ettl_, Oct 29 2012 */
%Y Cf. A184163, A218270, A218271
%K nonn
%O 0,4
%A _Nico Brown_, Oct 24 2012
%E a(6) and a(7) corrected by _Martin Ettl_, Oct 29 2012