# A006658 (b-file synthesized from sequence entry) 3 5 4 56 5 580 6 5894 7 60312 8 624240 9 6540510 10 69323910 11 742518832 12 8028001566 13 87526544560 14 961412790002 15 10630964761766 16 118257400015312 17 1322564193698320 18 14863191405246888 19 167771227744292160 20 1901345329566422790