Centered icosahedral (or cuboctahedral) numbers, also crystal ball sequence for f.c.c. lattice.

Terms

a(0) =1a(1) =13a(2) =55a(3) =147a(4) =309a(5) =561a(6) =923a(7) =1415a(8) =2057a(9) =2869a(10) =3871a(11) =5083a(12) =6525a(13) =8217a(14) =10179a(15) =12431a(16) =14993a(17) =17885a(18) =21127a(19) =24739a(20) =28741a(21) =33153a(22) =37995a(23) =43287a(24) =49049a(25) =55301a(26) =62063a(27) =69355a(28) =77197a(29) =85609