128672domain: NAppears in sequencesSum of a(n) terms of 1/k^(9/10) first exceeds n.at n=23A056186Numbers k such that phi(6k) is either phi(6k-2) or phi(6k+2), where phi is Euler's totient function A000010.at n=32A279011Numbers k such that phi(6k) = phi(6k-2), where phi is Euler's totient function A000010.at n=18A279183