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%I #10 Sep 08 2022 08:45:37
%S 89,359,809,1439,4409,8999,10889,12959,20249,23039,35999,47609,51839,
%T 56249,65609,75689,98009,116639,123209,129959,136889,143999,151289,
%U 158759,166409,234089,272249,282239,302759,313289,334889,404009,416159
%N Primes of the form 10*k^2 - 1.
%H Vincenzo Librandi, <a href="/A143828/b143828.txt">Table of n, a(n) for n = 1..5000</a>
%t p = 10; a = {}; Do[k = p x^2 - 1; If[PrimeQ[k], AppendTo[a, k]], {x, 1, 1000}]; a
%t Select[Table[10n^2-1,{n,1,800}],PrimeQ] (* _Vincenzo Librandi_, Dec 07 2011 *)
%o (Magma) [a: n in [1..400] | IsPrime(a) where a is 10*n^2-1]; // _Vincenzo Librandi_, Dec 07 2011
%Y Cf. A066436, A066049, A090686, A090684, A143826, A143827.
%K nonn,easy
%O 1,1
%A _Artur Jasinski_, Sep 02 2008
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