# A003774 (b-file synthesized from sequence entry) 1 4 2 48 3 672 4 8496 5 106944 6 1349760 7 17032800 8 214925952 9 2712031104 10 34221651456 11 431824387584 12 5448956749824 13 68757417818112 14 867612411420672 15 10947928532312064 16 138145948088696832