A201964 - OEIS

%I #6 Sep 08 2022 08:46:01

%S 31,151,241,631,991,1201,1951,2551,4831,5281,9601,11551,12241,13681,

%T 14431,15991,18481,24001,27031,28081,30241,37201,38431,48991,53281,

%U 54751,57751,59281,62401,67231,68881,73951,77431,79201,84631

%N Primes of the form 10n^2 - 9.

%H Vincenzo Librandi, <a href="/A201964/b201964.txt">Table of n, a(n) for n = 1..5000</a>

%t Select[Table[10n^2-9,{n,1,600}],PrimeQ]

%o (Magma) [a: n in [1..200] | IsPrime(a) where a is 10*n^2-9];

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Dec 07 2011