Number of fixed hexagonal polygons (or benzenoids) with n cells.

A121220

Number of fixed hexagonal polygons (or benzenoids) with n cells.

Terms

    a(0) =1a(1) =3a(2) =11a(3) =44a(4) =186a(5) =813a(6) =3640a(7) =16590a(8) =76663a(9) =358195a(10) =1688784a(11) =8022273a(12) =38351973a(13) =184353219a(14) =890371070a(15) =4318095442a(16) =21018564402a(17) =102642526470a(18) =502709028125

External references