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A245495 Primes of the form  n! - (n+1)! + (n+2)! + 1. 1

%I

%S 103,4441,36650881,5787936001,19702293811201,1075342687614074880001,

%T 8547762518578406446202880000001,

%U 59043709472234119545920159524322926688993280000000001,698533028148544417308552639358841460358000936394290829866303488000000000001

%N Primes of the form n! - (n+1)! + (n+2)! + 1.

%C The next term a(10) has 95 digits which is too large to show in data section.

%C a(16) has 1181 digits, hence not included in b-file.

%C 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 K. D. Bajpai, <a href="/A245495/b245495.txt">Table of n, a(n) for n = 1..15</a>

%e m = 3: m! - (m+1)! + (m+2)! + 1 = 103, which is prime, hence appears in the sequence.

%e m = 5: m! - (m+1)! + (m+2)! + 1 = 4441, which is prime, hence appears in the sequence.

%t Select[Table[n! - (n + 1)! + (n + 2)! + 1, {n, 200}], PrimeQ[#] &]

%o (PARI)

%o a(n) = p=n!-(n+1)!+(n+2)!+1;if(ispseudoprime(p),return(p))

%o n=1;while(n<100,if(a(n),print1(a(n),", "));n++) \\ _Derek Orr_, Jul 27 2014

%Y Cf. A000040, A049984, A049432.

%K nonn

%O 1,1

%A _K. D. Bajpai_, Jul 24 2014

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Last modified December 7 05:14 EST 2019. Contains 329839 sequences. (Running on oeis4.)