4855986044domain: NAppears in sequencesa(n) = binomial(4*n+1,n)*2/(3*n+2).at n=12A069271a(3n+k) = (k+1)*binomial(4n+k, n)/(3n+k+1), where k is n reduced mod 3.at n=37A124753Number of achiral polyominoes composed of n pentagonal cells of the hyperbolic regular tiling with Schläfli symbol {5,oo}.at n=24A369472