1384230domain: NAppears in sequencesNumbers k such that k and k^2+1 have equal sums of distinct prime divisors.at n=1A362152a(n+1) is the least k such that k - (a(n-1)+a(n)) and k + (a(n-1)+a(n)) are primes; a(0)=0, a(1)=1.at n=27A381328