Number of self-avoiding polygons with perimeter n on hexagonal [ =triangular ] lattice.

A036418

Number of self-avoiding polygons with perimeter n on hexagonal [ =triangular ] lattice.

Terms

    a(0) =0a(1) =0a(2) =2a(3) =3a(4) =6a(5) =15a(6) =42a(7) =123a(8) =380a(9) =1212a(10) =3966a(11) =13265a(12) =45144a(13) =155955a(14) =545690a(15) =1930635a(16) =6897210a(17) =24852576a(18) =90237582a(19) =329896569a(20) =1213528736a(21) =4489041219a(22) =16690581534a(23) =62346895571a(24) =233893503330a(25) =880918093866

External references