Number of -n..n arrays of 5 elements with first, second and third differences also in -n..n.

Terms

a(0) =27a(1) =293a(2) =1509a(3) =5205a(4) =14063a(5) =32267a(6) =65773a(7) =122709a(8) =213697a(9) =352075a(10) =554381a(11) =840659a(12) =1234569a(13) =1764039a(14) =2461495a(15) =3363883a(16) =4513485a(17) =5958085a(18) =7750859a(19) =9951423a(20) =12625883a(21) =15846605a(22) =19693499a(23) =24253977a(24) =29622535a(25) =35902357a(26) =43205125a(27) =51650425