Expansion of phi_{7, 4}(x) where phi_{r, s}(x) = Sum_{n, m>0} m^r * n^s * x^{m*n}.

Terms

a(0) =0a(1) =1a(2) =144a(3) =2268a(4) =18688a(5) =78750a(6) =326592a(7) =825944a(8) =2396160a(9) =4966677a(10) =11340000a(11) =19501812a(12) =42384384a(13) =62777078a(14) =118935936a(15) =178605000a(16) =306774016a(17) =410422194a(18) =715201488a(19) =894002060a(20) =1471680000a(21) =1873240992a(22) =2808260928a(23) =3405105288a(24) =5434490880a(25) =6152734375a(26) =9039899232