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A143932 a(n) = smallest positive prime number of the form x^2 - n! (where x is a positive integer). 2

%I

%S 3,2,3,97,241,241,1201,3361,5569,61441,240769,915049,240769,17302321,

%T 7076521,49186201,2100735289,1074527281,23971813321,32354445841,

%U 68820869329,2992426816129,26238323995129,104071698229321

%N a(n) = smallest positive prime number of the form x^2 - n! (where x is a positive integer).

%C For smallest positive integers x see A143931. Prime x see A143933.

%e a(1)=3 because 2^2 - 1! = 3;

%e a(2)=2 because 2^2 - 2! = 2;

%e a(3)=3 because 3^2 - 3! = 3;

%e a(4)=97 because 11^2 - 4! = 97.

%t b = {}; Do[k = Round[Sqrt[n! ]] + 1; While[ ! PrimeQ[k^2 - n! ], k++ ]; AppendTo[b, k^2-n! ], {n, 1, 50}]; b

%Y Cf. A121926, A143931, A143933.

%K nonn

%O 1,1

%A _Artur Jasinski_, Sep 05 2008

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Last modified May 22 12:28 EDT 2022. Contains 353950 sequences. (Running on oeis4.)