2,3

Hugo Pfoertner, Table of n, a(n) for n = 2..10000

a(2) = 1 because 7 is the greatest prime < 3^2 and 5 is the least prime > 2^2. (7-5)/2 = 1.

(PARI) for(n=2, 69, print1((precprime((n+1)^2)-nextprime(n^2))/2, ", "))

Cf. A007491, A053001, A132657.

Sequence in context: A154947 A152747 A010847 * A082129 A159970 A096374

Adjacent sequences: A331695 A331696 A331697 * A331699 A331700 A331701

nonn

Hugo Pfoertner, Jan 27 2020

approved