The first Zagreb index of the Aztec diamond AZ(n) (see the Ramanes et al. reference, Theorem 2.1).

Terms

a(0) =68a(1) =212a(2) =420a(3) =692a(4) =1028a(5) =1428a(6) =1892a(7) =2420a(8) =3012a(9) =3668a(10) =4388a(11) =5172a(12) =6020a(13) =6932a(14) =7908a(15) =8948a(16) =10052a(17) =11220a(18) =12452a(19) =13748a(20) =15108a(21) =16532a(22) =18020a(23) =19572a(24) =21188a(25) =22868a(26) =24612a(27) =26420a(28) =28292a(29) =30228