3*n*(9n + 2)*(18n - 1), where n runs through the odd numbers 1, 3, 5,...

Terms

a(0) =561a(1) =13833a(2) =62745a(3) =170625a(4) =360801a(5) =656601a(6) =1081353a(7) =1658385a(8) =2411025a(9) =3362601a(10) =4536441a(11) =5955873a(12) =7644225a(13) =9624825a(14) =11921001a(15) =14556081a(16) =17553393a(17) =20936265a(18) =24728025a(19) =28952001a(20) =33631521a(21) =38789913a(22) =44450505a(23) =50636625a(24) =57371601a(25) =64678761a(26) =72581433a(27) =81102945a(28) =90266625