a(n+1) = n*(a(n) + 1) for n >= 1, a(1) = 1.

Terms

a(0) =1a(1) =2a(2) =6a(3) =21a(4) =88a(5) =445a(6) =2676a(7) =18739a(8) =149920a(9) =1349289a(10) =13492900a(11) =148421911a(12) =1781062944a(13) =23153818285a(14) =324153456004