Integer part of the volume of a regular tetrahedron with edge length n.

Terms

a(0) =0a(1) =0a(2) =3a(3) =7a(4) =14a(5) =25a(6) =40a(7) =60a(8) =85a(9) =117a(10) =156a(11) =203a(12) =258a(13) =323a(14) =397a(15) =482a(16) =579a(17) =687a(18) =808a(19) =942a(20) =1091a(21) =1254a(22) =1433a(23) =1629a(24) =1841a(25) =2071a(26) =2319a(27) =2587a(28) =2874a(29) =3181