OFFSET
1,1
LINKS
C. Hooley, On the greatest prime factor of a quadratic polynomial, Acta Mathematica July 1967, Volume 117, Issue 1, pp 281-299.
MAPLE
a:= proc(n) option remember; `if`(n=0, 0,
max(a(n-1), numtheory[factorset](n^2+1)[]))
end:
seq(a(n), n=1..55); # Alois P. Heinz, Jan 03 2021
MATHEMATICA
a[n_] := a[n] = If[n == 1, 2, Max[a[n-1], FactorInteger[n^2+1][[-1, 1]]]];
Table[a[n], {n, 1, 55}] (* Jean-François Alcover, May 14 2022, after Alois P. Heinz *)
PROG
(PARI) a(m) = {for (n=1, m, f = factor(prod(x=1, n, x^2+1)); print1(f[length(f~), 1], ", "); ); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Nov 23 2012
STATUS
approved