1/24 a^{c0}_{a0,a1,a2} b^{}_{c1,c2,c3,c4} c^{c3,c4}_{} a+(c1) a+(c2) a+(a0) a+(a1) a+(a2) a-(c0)
-1/36 a^{c0}_{a0,a1,a2} b^{}_{c1,c2,c3,c5} c^{c4,c5}_{} a+(c1) a+(c2) a+(c3) a+(a0) a+(a1) a+(a2) a-(c4) a-(c0)