Number of fixed hexagonal polyominoes with n cells that have a horizontal axis of symmetry that connects the midpoints of opposite edges of one of the n cells.

A347257

Number of fixed hexagonal polyominoes with n cells that have a horizontal axis of symmetry that connects the midpoints of opposite edges of one of the n cells.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =4a(4) =12a(5) =18a(6) =52a(7) =83a(8) =235a(9) =389a(10) =1087a(11) =1849a(12) =5110a(13) =8871a(14) =24310a(15) =42884a(16) =116706a(17) =208559a(18) =564322a(19) =1019362a(20) =2744769a(21) =5003180a(22) =13415317a(23) =24644438a(24) =65839497a(25) =121769444a(26) =324271545a(27) =603304529a(28) =1602013491a(29) =2996240586

External references