# A009431 (b-file synthesized from sequence entry) 0 0 1 1 2 -1 3 -1 4 0 5 49 6 -165 7 -393 8 -504 9 70785 10 -434385 11 -517265 12 -12647976 13 654552625 14 -6276987717 15 18362076327 16 -636272644560 17 22683808563841 18 -312594994151361 19 2817355930176479 20 -72112751626318640 21 2222078368780722865