%I #35 Jan 15 2021 20:57:44
%S 5,21,421,176821,31265489221,977530816197201697621,
%T 955566496615167328821993756200407115362021,
%U 913107329453384594090655605142589591944556891901674138343716072975722193082773842421
%N Variant of Sylvester's sequence: a(n+1) = a(n)^2 - a(n) + 1, with a(1) = 5.
%H Mohammad K. Azarian, <a href="http://www.jstor.org/stable/10.4169/college.math.j.42.4.329">Sylvester's Sequence and the Infinite Egyptian Fraction Decomposition of 1, Problem 958</a>, College Mathematics Journal, Vol. 42, No. 4, September 2011, p. 330.
%H Mohammad K. Azarian, <a href="http://www.jstor.org/stable/10.4169/college.math.j.43.4.337">Sylvester's Sequence and the Infinite Egyptian Fraction Decomposition of 1, Solution</a>, College Mathematics Journal, Vol. 43, No. 4, September 2012, pp. 340-342.
%F a(n) = round(2.127995907464107054577351...)^(2^n) = round(A144803^(2^n)). [corrected by _Joerg Arndt_, Jan 15 2021]
%F a(n+1) = a(n)^2 - a(n) + 1, with a(1) = 5.
%e a(0) = 4, a(1) = 4+1 = 5, a(2) = 4*5+1 = 21, a(3) = 4*5*21+1 = 421, a(4) = 4*5*21*421+1 = 176821, ... - _Philippe Deléham_, Apr 19 2013
%t a = {}; k = 5; Do[AppendTo[a, k]; k = k^2 - k + 1, {n,1,10}]; a (* _Artur Jasinski_, Sep 21 2008 *)
%t NestList[#^2-#+1&,5,8] (* _Harvey P. Dale_, Jan 17 2012 *)
%Y Cf. A000058, A082732, A144780, A144781, A144782, A144783, A144784, A144785, A144786, A144787, A144788.
%K nonn
%O 1,1
%A _Artur Jasinski_, Sep 21 2008