Number of inequivalent (mod D_3) ways to place 3 points on a triangular grid of side n so that they are not vertices of an equilateral triangle with sides parallel to the grid.
A243208
Number of inequivalent (mod D_3) ways to place 3 points on a triangular grid of side n so that they are not vertices of an equilateral triangle with sides parallel to the grid.
Terms
- a(0) =0a(1) =3a(2) =20a(3) =77a(4) =223a(5) =552a(6) =1196a(7) =2380a(8) =4388a(9) =7657a(10) =12710a(11) =20301a(12) =31297a(13) =46892a(14) =68426a(15) =97674a(16) =136596a(17) =187713a(18) =253770a(19) =338217a(20) =444773a(21) =578018a(22) =742852a(23) =945210a(24) =1191398a(25) =1488949a(26) =1845824a(27) =2271415a(28) =2775605a(29) =3369930
External references
- oeis: A243208