%I A129550
%S A129550 1,1,8,20,98,293,1128,3409,10846,30480,84652,217677,544312,1289225,
%T A129550 2961626,6528284,13980717,28963980,58464510,114806429,220298632,
%U A129550 412950779,758418342,1365044296,2412766496,4189995629,7159916414
%N A129550 Number of real polynomial invariants for the action of 4 copies of U(2) 
               on the fourth tensor power of C^2.
%D A129550 Nolan R. Wallach, The Hilbert series for measures of entanglement in 
               4 qubits, Acta Appl. Math. 86(2005),203-220.
%F A129550 G.f.: (R(q) + q^76*R(1/q))/((1 - q^2)*(1 - q^4)^7*(1 - q^6)^6*(1 - q^8)^4*(1 
               - q^10)) where R(q) = 1 + 6*q^6 + 46*q^8 + 110*q^10 + 344*q^12 + 
               844*q^14 + 2154*q^16 + 4606*q^18 + 9397*q^20 + 16848*q^22 + 28747*q^24 
               + 44580*q^26 + 65366*q^28 + 88036*q^30 + 111909*q^32 + 131368*q^34 
               + 145676*q^36 + 149860/2*q^38.
%Y A129550 Cf. A129548, A129549.
%Y A129550 Sequence in context: A003685 A066011 A007016 this_sequence A014584 A074472 
               A094253
%Y A129550 Adjacent sequences: A129547 A129548 A129549 this_sequence A129551 A129552 
               A129553
%K A129550 nonn
%O A129550 0,3
%A A129550 Mike Zabrocki (zabrocki(AT)mathstat.yorku.ca), Apr 20 2007