# A007683 (b-file synthesized from sequence entry) 1 1 2 -3 3 3 4 9 5 21 6 -33 7 -1173 8 -13515 9 -113739 10 -532209 11 6284379 12 264830061 13 5897799141 14 104393462439 15 1459983940203 16 10308316834293 17 -308010522508395 18 -19576840707893409 19 -726806556195360069 20 -22261372611370303875 21 -591210850189999983099