Surface area of Johnson square pyramid (rounded down) with all the edge-lengths equal to n.

Terms

a(0) =2a(1) =10a(2) =24a(3) =43a(4) =68a(5) =98a(6) =133a(7) =174a(8) =221a(9) =273a(10) =330a(11) =393a(12) =461a(13) =535a(14) =614a(15) =699a(16) =789a(17) =885a(18) =986a(19) =1092a(20) =1204a(21) =1322a(22) =1445a(23) =1573a(24) =1707a(25) =1846a(26) =1991a(27) =2141a(28) =2297a(29) =2458