86762domain: NAppears in sequencesNumbers n such that sigma(2*phi(n)) = 2*sigma(n).at n=31A137733Expansion of Product_{k>=1} ((1 + x^k) / (1 - x^(3*k)))^k.at n=22A285446Triangle read by rows: T(n,r), 0 <= r <= n, is the number of idempotents of rank r in the twisted planar partition monoid PP_n^tau.at n=30A289620