Harary-Read numbers: restricted hexagonal polyominoes (cata-polyhexes) with n cells.

A002216

Harary-Read numbers: restricted hexagonal polyominoes (cata-polyhexes) with n cells.

Terms

    a(0) =0a(1) =1a(2) =1a(3) =2a(4) =5a(5) =12a(6) =37a(7) =123a(8) =446a(9) =1689a(10) =6693a(11) =27034a(12) =111630a(13) =467262a(14) =1981353a(15) =8487400a(16) =36695369a(17) =159918120a(18) =701957539a(19) =3101072051a(20) =13779935438a(21) =61557789660a(22) =276327463180

External references