31670domain: NAppears in sequencesNumbers k such that phi(k) + phi(k+1) = k+2.at n=21A067797G.f.: Product_{m>0} (1+x^m+2!*x^(2*m)).at n=43A293204Number of permutations of [n] in which the length of every increasing run is 0 or 1 (mod 3).at n=9A322251