a(n) is the number of 4 element sets of integer sided trapezoids with distinct areas and base angles that are 60 degrees, which fill an equilateral triangular grid of side n units.
A389518
a(n) is the number of 4 element sets of integer sided trapezoids with distinct areas and base angles that are 60 degrees, which fill an equilateral triangular grid of side n units.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =9a(6) =20a(7) =36a(8) =62a(9) =99a(10) =136a(11) =203a(12) =264a(13) =349a(14) =455a(15) =574a(16) =709a(17) =866a(18) =1035a(19) =1249a(20) =1470a(21) =1707a(22) =1979a(23) =2302a(24) =2636a(25) =2983a(26) =3386a(27) =3826a(28) =4277a(29) =4789
External references
- oeis: A389518