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%I #20 Oct 30 2022 18:19:59
%S 11,7,31,41,17,61,71,3,13,101,37,11,131,47,151,23,19,181,191,67,211,
%T 17,11,241,251,29,271,281,97,43,311,107,331,31,13,19,53,127,23,401,
%U 137,421,431,7,41,461,157,37,491,167,73,521,59,541,29,17,571,83,197,601,47
%N Largest prime factor of 10*n + 1.
%H Harry J. Smith, <a href="/A060954/b060954.txt">Table of n, a(n) for n = 1..1000</a>
%H László Tóth, <a href="http://arxiv.org/abs/1404.4214">Counting solutions of quadratic congruences in several variables revisited</a>, arXiv preprint arXiv:1404.4214 [math.NT], 2014.
%H László Tóth, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL17/Toth/toth12.html">Counting Solutions of Quadratic Congruences in Several Variables Revisited</a>, J. Int. Seq. 17 (2014), # 14.11.6.
%e 21 = 3*7, so a(2) = 7.
%t Table[First[Last[FactorInteger[10n + 1]]], {n, 1, 80}]
%o (PARI) { for (n=1, 1000, f=factor(10*n + 1)~; write("b060954.txt", n, " ", f[1, length(f)]); ) } \\ _Harry J. Smith_, Jul 19 2009
%o (Python)
%o from sympy import factorint
%o def a(n): return max(factorint(10*n+1))
%o print([a(n) for n in range(1, 62)]) # _Michael S. Branicky_, Nov 07 2021
%K nonn
%O 1,1
%A _J. Lowell_, May 08 2001
%E More terms from _Reiner Martin_, Jul 07 2001
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