%I #6 Sep 08 2022 08:46:01
%S 11,41,251,491,641,811,2251,4001,6761,7841,9001,10891,12251,13691,
%T 16001,16811,22091,23041,32491,33641,40961,50411,68891,72251,73961,
%U 81001,82811,86491,98011,108161,110251,112361,121001,125441,127691
%N Primes of the form 10n^2 + 1.
%H Vincenzo Librandi, <a href="/A201709/b201709.txt">Table of n, a(n) for n = 1..5000</a>
%t Select[Table[10n^2+1,{n,0,800}],PrimeQ]
%o (Magma) [a: n in [0..300] | IsPrime(a) where a is 10*n^2+1];
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Dec 04 2011