E.g.f.: log(1 - log(1 - x))^2 / 2.

Terms

a(0) =1a(1) =0a(2) =4a(3) =5a(4) =58a(5) =217a(6) =2035a(7) =13470a(8) =134164a(9) =1243770a(10) =14129410a(11) =164244808a(12) =2151576620a(13) =29671566836a(14) =444758323628