%I
%S 1,2,30,259,429,4612,26466,88110,31545,104071,2775456,14614604,
%T 15793779,164082567,476853784,495207013,3613011290,9032608100,
%U 69827848342
%N Least number k for which primepi(prime(k+1)/2)  primepi(prime(k)/2) = n.
%C See A215238 and A215239 for prime(a(n)) and the next prime.
%C Equivalently stated, a(n) is least k such that there are exactly n primes between prime(k)/2 and prime(k+1)/2.  _Peter Munn_, May 20 2019
%e For n = 2, the consecutive primes are 113 and 127; there are two primes between 56.5 and 63.5. For n = 3, the consecutive primes are 1637 and 1657; there are three primes between 818.5 and 828.5.
%t t = Table[PrimePi[Prime[n+1]/2]  PrimePi[Prime[n]/2], {n, 100000}]; Flatten[Table[Position[t, n, 1, 1], {n, 0, 8}]]
%Y Cf. A217564, A215238, A215239.
%K nonn,more,hard
%O 0,2
%A _T. D. Noe_, Oct 09 2012
%E a(14)a(18) from _Donovan Johnson_, Oct 13 2012
