220568domain: NAppears in sequencesa(n) = Sum_{0 <= i < j <= n} (prime(j) - prime(i))^2, where prime(0) = 1.at n=19A024526Starting positions of strings of four 9's in the decimal expansion of Pi.at n=27A083643Starting positions of strings of five 9's in the decimal expansion of Pi.at n=7A083644