Duplicate of A076978.

Terms

a(0) =1a(1) =2a(2) =6a(3) =30a(4) =6a(5) =210a(6) =6a(7) =2310a(8) =2730a(9) =30a(10) =39270a(11) =7410a(12) =42a(13) =7590a(14) =46410a(15) =1272810a(16) =30a(17) =930930a(18) =82110a(19) =6a(20) =21111090a(21) =1230a(22) =48969690