Number of n-node trees not determined by their spectra.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =2a(8) =10a(9) =8a(10) =60a(11) =119a(12) =415a(13) =826a(14) =2470a(15) =5246a(16) =14944a(17) =32347a(18) =84118