Number of tilings of an equilateral triangle of side length n with unit triangles (of side length 1) and exactly four unit "lozenges" or "diamonds" (also of side length 1).

A326369

Number of tilings of an equilateral triangle of side length n with unit triangles (of side length 1) and exactly four unit "lozenges" or "diamonds" (also of side length 1).

Terms

    a(0) =0a(1) =0a(2) =0a(3) =762a(4) =12699a(5) =90270a(6) =417435a(7) =1478160a(8) =4354497a(9) =11203269a(10) =25970895a(11) =55414395a(12) =110505120a(13) =208300257a(14) =374375664a(15) =645922095a(16) =1075615380a(17) =1736379630a(18) =2727171042a(19) =4179918384a(20) =6267764745a(21) =9214763640a(22) =13307191065a(23) =18906643602a(24) =26465101179a(25) =36542141595a(26) =49824502425

External references