A099499 - OEIS

%I #13 Sep 08 2022 08:45:15

%S 17,162287,2486784401,83695120256591,

%T 84721522804414816904952398305908708011513455440403306207160333176150520399

%N Primes of the form A007925(n)=n^(n+1)-(n+1)^n.

%C The next term a(6)=883^884-884^883 has 2605 decimal digits and is too large to display.

%e a(2)=162287 because A007925(A072179(2))=6^7-7^6=162287 is prime.

%t Select[Table[n^(n+1)-(n+1)^n,{n,0,1000}],PrimeQ] (* _Vincenzo Librandi_, Jul 18 2012 *)

%o (Magma) [a: n in [0..50] | IsPrime(a) where a is n^(n+1)-(n+1)^n ]; // _Vincenzo Librandi_, Jul 18 2012

%Y Cf. A007925 n^(n+1)-(n+1)^n, A072179 n^(n+1)-(n+1)^n is prime, A099497 n^(n+1)-(n+1)^n is a semiprime, A099498 semiprimes of the form n^(n+1)-(n+1)^n.

%K nonn

%O 1,1

%A _Hugo Pfoertner_, Oct 19 2004