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Largest number x such that the greatest prime factor of x^2+2 is A033203(n), the n-th prime not congruent to 5 or 7 mod 8.
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%I #6 Mar 30 2012 17:28:27

%S 22,140,707,21362,4991,1306066,137965,2294636,31768298,1557652,

%T 340064590,38439662,105080665,273502688,543164542,9575480365630,

%U 391890109484,14629598023,80849485336,1241646894380

%N Largest number x such that the greatest prime factor of x^2+2 is A033203(n), the n-th prime not congruent to 5 or 7 mod 8.

%C For any prime p, there are finitely many x such that x^2+2 has p as its largest prime factor.

%H Filip Najman, <a href="http://web.math.hr/~fnajman/smooth.pdf">Smooth values of some quadratic polynomials</a>, Glasnik Matematicki Series III 45 (2010), pp. 347-355.

%H Filip Najman, <a href="http://web.math.hr/~fnajman/">Home Page</a> (gives all 914 numbers x such that x^2+2 has no prime factor greater than 193)

%Y Equivalents for other polynomials: A175607 (x^2 - 1), A145606 (x^2 + x), A185389 (x^2 + 1), A185396 (x^2 - 2).

%K nonn

%O 1,1

%A _Charles R Greathouse IV_, Feb 21 2011