Total number of triangles visible in regular n-gon with all diagonals drawn.

Terms

a(0) =1a(1) =8a(2) =35a(3) =110a(4) =287a(5) =632a(6) =1302a(7) =2400a(8) =4257a(9) =6956a(10) =11297a(11) =17234a(12) =25935a(13) =37424a(14) =53516a(15) =73404a(16) =101745a(17) =136200a(18) =181279a(19) =236258a(20) =306383a(21) =389264a(22) =495650a(23) =620048a(24) =772785a(25) =951384a(26) =1167453a(27) =1410350a(28) =1716191a(29) =2058848