Truncated octahedron with faces of centered polygons.

Terms

a(0) =1a(1) =39a(2) =185a(3) =511a(4) =1089a(5) =1991a(6) =3289a(7) =5055a(8) =7361a(9) =10279a(10) =13881a(11) =18239a(12) =23425a(13) =29511a(14) =36569a(15) =44671a(16) =53889a(17) =64295a(18) =75961a(19) =88959a(20) =103361a(21) =119239a(22) =136665a(23) =155711a(24) =176449a(25) =198951a(26) =223289a(27) =249535a(28) =277761a(29) =308039