# A013149 (b-file synthesized from sequence entry) 0 1 1 4 2 -16 3 64 4 4096 5 -480896 6 54717440 7 -7775895552 8 1454255472640 9 -360442602684416 10 116460747215831040 11 -47685470462142971904 12 24020257118743960748032 13 -14514884376044102613991424