-1/12 a^{a0}_{} b^{}_{c0,c1,c2,c3} c^{c3}_{a1,a2} a+(c0) a+(c1) a+(c2) a+(a1) a+(a2) a-(a0)
+1/6 a^{a1}_{} b^{}_{c0,c1,c2,c3} c^{c3}_{a0,a2} eta1^{a2}_{a1} a+(c0) a+(c1) a+(c2) a+(a0)
-1/24 a^{a1}_{} b^{}_{c0,c1,c2,c3} c^{c4}_{a0,a2} eta1^{a2}_{a1} a+(c0) a+(c1) a+(c2) a+(c3) a+(a0) a-(c4)