%I #7 Jul 17 2021 11:21:18
%S 27,9,9,9,7,27,7,9,19,9,21,1,267,47,1,69,307,19,585,37,147,313,159,
%T 251,99,73,355,197,225,545,99,5,481,2359,337,285,95,993,903,279,779,
%U 123,519,1201,1717,1551,261,123,1649,1571,87,1325,537,201,2131,1403,205,863
%N Least k such that k*prime(n)#/2 - 4 and k*prime(n)#/2 + 2 are consecutive primes, where prime(n)# is the n-th primorial.
%e 27*2/2 = 27, 23 and 29 are consecutive primes so a(1) = 27.
%e 9*2*3/2 = 27 so a(2) = 9.
%t a[n_] := Module[{k = 1, p = Product[Prime[i], {i,1,n}]}, While[!(PrimeQ[k*p/2-4] && NextPrime[k*p/2-4] == k*p/2+2), k++]; k]; Array[a, 60] (* _Amiram Eldar_, Jul 17 2021 *)
%Y Cf. A002110.
%Y Cf. A097439, A097440, A097570, A098064.
%K nonn
%O 1,1
%A _Pierre CAMI_, Aug 22 2004