%I #15 Sep 08 2022 08:44:47

%S 1,1,1,2,3,2,3,2,3,2,3,3,4,3,3,3,3,3,3,4,2,3,3,2,3,4,3,4,2,3,4,4,3,3,

%T 3,3,2,3,4,3,3,3,4,2,3,3,5,3,5,3,3,2,3,3,2,4,3,3,3,3,3,4,3,3,3,4,3,3,

%U 4,3,3,4,4,3,3,4,4,4,4,6,3,4,3,2,2,3,2

%N Number of distinct prime divisors of prime(n)*prime(n-1) + 1.

%C This is taking prime(0)=1. - _Robert Israel_, Dec 22 2015

%H Robert Israel, <a href="/A023524/b023524.txt">Table of n, a(n) for n = 1..10000</a>

%p 1,seq(nops(numtheory:-factorset(ithprime(n)*ithprime(n-1)+1)), n=2..100); # _Robert Israel_, Dec 22 2015

%t Prepend[Table[PrimeNu[Prime@ n Prime[n - 1] + 1], {n, 2, 80}], 1] (* _Michael De Vlieger_, Dec 22 2015 *)

%o (PARI) a(n) = if (n==1, 1, omega(prime(n)*prime(n-1) + 1)); \\ _Michel Marcus_, Dec 22 2015

%o (Magma) [#PrimeDivisors((NthPrime(n)*(NthPrime(n-1))+1)): n in [1..100]]; // _Vincenzo Librandi_, Dec 23 2015

%K nonn

%O 1,4

%A _Clark Kimberling_