Site percolation series for hexagonal net.

Terms

a(0) =1a(1) =-1a(2) =-4a(3) =-16a(4) =-73a(5) =-341a(6) =-1659a(7) =-8483a(8) =-44144a(9) =-236626a(10) =-1282073a(11) =-7078309a(12) =-39389088a(13) =-221480060a(14) =-1259127130a(15) =-7134579098a(16) =-41630476786a(17) =-232579012470