Number of second differences of arrays of length 4 of numbers in 0..n.

Terms

a(0) =15a(1) =49a(2) =103a(3) =177a(4) =271a(5) =385a(6) =519a(7) =673a(8) =847a(9) =1041a(10) =1255a(11) =1489a(12) =1743a(13) =2017a(14) =2311a(15) =2625a(16) =2959a(17) =3313a(18) =3687a(19) =4081a(20) =4495a(21) =4929a(22) =5383a(23) =5857a(24) =6351a(25) =6865a(26) =7399a(27) =7953a(28) =8527a(29) =9121