Number of second differences of arrays of length 8 of numbers in 0..n.

Terms

a(0) =255a(1) =6305a(2) =58975a(3) =320481a(4) =1225631a(5) =3693505a(6) =9399615a(7) =21108545a(8) =43067071a(9) =81457761a(10) =144913055a(11) =245089825a(12) =397304415a(13) =621228161a(14) =941643391a(15) =1389259905a(16) =2001591935a(17) =2823895585a(18) =3910166751a(19) =5324199521a(20) =7140705055a(21) =9446490945