# A015968 (b-file synthesized from sequence entry) 1 1 2 2 3 226 4 25538 5 2885794 6 326094722 7 36848703586 8 4163903505218 9 470521096089634 10 53168883858128642 11 638026606623638426 12 6008083875968536546 13 6789793858544278594