C20 := (-1/2217600*lambda[4]^4-1/2217600*lambda[4]^2*lambda[3]+79/17740800*
lambda[3]^2+1/1478400*lambda[4]*lambda[2]-1/59136*lambda[1])*v[4]^12*v[2]^2+(
23/8072064000*lambda[4]^4-173/16144128000*lambda[4]^2*lambda[3]-211/
51661209600*lambda[3]^2+1/39137280*lambda[4]*lambda[2]+1/172204032*lambda[1])*
v[4]^16*v[3]^2+(-3/80*lambda[3]^2-1/60*lambda[4]*lambda[2]+1/60*lambda[1])*v[3
]^6*v[2]^2+(1/4480*lambda[4]*lambda[2]+1/2240*lambda[1])*v[4]^9*v[3]^2*v[1]+(-\
1/160*lambda[4]*lambda[2]-1/80*lambda[1])*v[4]^5*v[3]^4*v[1]+(1/28828800*
lambda[4]^4-1/3603600*lambda[4]^2*lambda[3]+1/1801800*lambda[3]^2-1/7687680*
lambda[4]*lambda[2]-1/3843840*lambda[1])*v[4]^13*v[1]+lambda[1]*v[3]*v[2]*v[1]
^2+(1/40*lambda[4]*lambda[2]+1/20*lambda[1])*v[4]^5*v[2]^2*v[1]+(-1/120*lambda
[4]*lambda[2]-1/60*lambda[1])*v[4]*v[3]^6*v[1]+1/4*lambda[3]^2*v[4]^2*v[3]^3*v
[2]^3+(1/120*lambda[4]^2*lambda[3]+1/240*lambda[3]^2)*v[4]^6*v[3]*v[2]^3+(1/
1120*lambda[4]^2*lambda[3]+13/8960*lambda[3]^2+1/2240*lambda[4]*lambda[2]-1/
448*lambda[1])*v[4]^8*v[3]^2*v[2]^2+(-3/64*lambda[3]^2-1/48*lambda[4]*lambda[2
]-1/16*lambda[1])*v[4]^4*v[3]^4*v[2]^2+(-3/560*lambda[3]^2-1/420*lambda[4]*
lambda[2]-2/105*lambda[1])*v[4]^2*v[3]^7*v[2]+(-31/6134768640000*lambda[4]^4+
31/1226953728000*lambda[4]^2*lambda[3]-79/3926251929600*lambda[3]^2-1/
32718766080*lambda[4]*lambda[2]+1/13087506432*lambda[1])*v[4]^20+(1/33600*
lambda[4]^2*lambda[3]+1/26880*lambda[3]^2+1/33600*lambda[4]*lambda[2])*v[4]^10
*v[3]^3*v[2]+(-1/800*lambda[4]^2*lambda[3]-1/1600*lambda[3]^2-1/400*lambda[4]*
lambda[2])*v[4]^6*v[3]^5*v[2]+(-1/28828800*lambda[4]^4+5/32288256*lambda[4]^2*
lambda[3]-401/1614412800*lambda[3]^2+1/134534400*lambda[4]*lambda[2]+1/672672*
lambda[1])*v[4]^14*v[3]*v[2]+1/4*lambda[1]*v[4]^2*v[3]^2*v[1]^2+(1/8870400*
lambda[4]^4+1/8870400*lambda[4]^2*lambda[3]-79/70963200*lambda[3]^2+1/591360*
lambda[4]*lambda[2]+1/236544*lambda[1])*v[4]^12*v[3]^4+(-1/67200*lambda[4]^2*
lambda[3]-13/537600*lambda[3]^2+1/67200*lambda[4]*lambda[2]+1/26880*lambda[1])
*v[4]^8*v[3]^6+(1/2*lambda[4]*lambda[2]+lambda[1])*v[4]*v[3]^2*v[2]^2*v[1]+(1/
22400*lambda[3]^2-1/8400*lambda[4]*lambda[2]+1/3360*lambda[1])*v[3]^10+(1/140*
lambda[4]*lambda[2]+1/70*lambda[1])*v[4]^7*v[3]*v[2]*v[1]+(1/32*lambda[3]^2-1/
8*lambda[1])*v[4]^4*v[2]^4+(3/8*lambda[3]^2+1/2*lambda[1])*v[3]^2*v[2]^4+(3/
17920*lambda[3]^2-1/2240*lambda[4]*lambda[2]-13/13440*lambda[1])*v[4]^4*v[3]^8
+1/80*lambda[1]*v[4]^6*v[1]^2;