A(x) satisfies A000290(x)/x^2 = A(x)/A(x^2); A000290 = integer squares.

Terms

a(0) =1a(1) =4a(2) =13a(3) =32a(4) =74a(5) =152a(6) =298a(7) =544a(8) =964a(9) =1632a(10) =2700a(11) =4320a(12) =6790a(13) =10408a(14) =15718a(15) =23264a(16) =34010a(17) =48920a(18) =69626a(19) =97760a(20) =136022a(21) =187112a(22) =255350a(23) =345056a(24) =463020a(25) =616032a(26) =814500a(27) =1068832a(28) =1394746a(29) =1807960