This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A245495 #22 Aug 20 2021 18:04:55 %S A245495 103,4441,36650881,5787936001,19702293811201,1075342687614074880001, %T A245495 8547762518578406446202880000001, %U A245495 59043709472234119545920159524322926688993280000000001,698533028148544417308552639358841460358000936394290829866303488000000000001 %N A245495 Primes of the form n! - (n+1)! + (n+2)! + 1. %C A245495 The next term a(10) has 95 digits which is too large to show in data section. %C A245495 a(16) has 1181 digits, hence not included in b-file. %C A245495 Primes for indices 3, 5, 9, 11, 14, 20, 27, 41, 54, 65, 81, 83, 105, 315, 323, 515, ... - _Robert G. Wilson v_, Aug 07 2014 %H A245495 K. D. Bajpai, <a href="/A245495/b245495.txt">Table of n, a(n) for n = 1..15</a> %e A245495 m = 3: m! - (m+1)! + (m+2)! + 1 = 103, which is prime, hence appears in the sequence. %e A245495 m = 5: m! - (m+1)! + (m+2)! + 1 = 4441, which is prime, hence appears in the sequence. %t A245495 Select[Table[n! - (n + 1)! + (n + 2)! + 1, {n, 200}], PrimeQ[#] &] %t A245495 Select[#[[1]]-#[[2]]+#[[3]]+1&/@Partition[Range[70]!,3,1],PrimeQ] (* _Harvey P. Dale_, Aug 20 2021 *) %o A245495 (PARI) %o A245495 a(n) = p=n!-(n+1)!+(n+2)!+1;if(ispseudoprime(p),return(p)) %o A245495 n=1;while(n<100,if(a(n),print1(a(n),", "));n++) \\ _Derek Orr_, Jul 27 2014 %Y A245495 Cf. A000040, A049984, A049432. %K A245495 nonn %O A245495 1,1 %A A245495 _K. D. Bajpai_, Jul 24 2014