45783domain: NAppears in sequencesNumber of planar n X n X n binary triangular grids symmetric both under 120 degree rotation and reflection with no more than 8 ones in any 4 X 4 X 4 subtriangle.at n=12A153961a(n) = Sum_{k=0..floor(n/10)} binomial(n-5*k,5*k).at n=27A348290