Start with the square tile of the Shield tiling and recursively apply the substitution rule. a(n) is the number of triangles with 6 markings after n iterations.

A298681

Start with the square tile of the Shield tiling and recursively apply the substitution rule. a(n) is the number of triangles with 6 markings after n iterations.

Terms

    a(0) =0a(1) =4a(2) =4a(3) =32a(4) =80a(5) =372a(6) =1236a(7) =4912a(8) =17728a(9) =67364a(10) =248996a(11) =934080a(12) =3476400a(13) =12993364a(14) =48453364a(15) =180907472a(16) =675001760a(17) =2519449092a(18) =9402095556a(19) =35090331232a(20) =130956433168a(21) =488740993844

External references