335856domain: NAppears in sequencesDivide primes in groups with 2n elements and add together.at n=28A109726Triangle T(n,k) read by rows (n >= 0, k >= 0) with g.f. 1/(1 - f(0)*x - x*y/(1 - f(1)*x - x*y/(1 - f(2)*x - x*y/(1 - f(3)*x - x*y/(1 - f(4)*x - x*y/(1 - ...)))))) where f(n) = n + 1 for n >= 0.at n=48A383019