The second Zagreb index of the Aztec diamond AZ(n) (see the Ramanes et al. reference, Theorem 2.2).

Terms

a(0) =96a(1) =352a(2) =736a(3) =1248a(4) =1888a(5) =2656a(6) =3552a(7) =4576a(8) =5728a(9) =7008a(10) =8416a(11) =9952a(12) =11616a(13) =13408a(14) =15328a(15) =17376a(16) =19552a(17) =21856a(18) =24288a(19) =26848a(20) =29536a(21) =32352a(22) =35296a(23) =38368a(24) =41568a(25) =44896a(26) =48352a(27) =51936a(28) =55648a(29) =59488