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Product of all primes in the interval ((n+1)/2,n].
2

%I #10 Nov 20 2023 15:31:34

%S 1,2,3,3,5,5,35,35,7,7,77,77,143,143,143,143,2431,2431,46189,46189,

%T 4199,4199,96577,96577,7429,7429,7429,7429,215441,215441,6678671,

%U 6678671,392863,392863,392863,392863,765049,765049,765049,765049,31367009,31367009,1348781387

%N Product of all primes in the interval ((n+1)/2,n].

%C The case n=1 is special and defined conventionally.

%C a(n) = A034386(n)/A034386(1+floor((n+1)/2)).

%C Notice that the interval is semiopen; a prime p is included in the product if (n+1)<2p<=2n.

%H Stanislav Sykora, <a href="/A212792/b212792.txt">Table of n, a(n) for n = 1..1000</a>

%e a(13) = product of all primes in (7,13] = 11*13 = 143.

%o (PARI) {p2(n) = result=1;forprime(p=1+floor((n+1)\2),n,result=result*p);}

%Y Cf. A212791, A034386.

%K nonn

%O 1,2

%A _Stanislav Sykora_, May 27 2012