a(n)=Sum_{i=0..n} |stirling1(n,i)|*2^(2^i).A059588a(n)=Sum_{i=0..n} |stirling1(n,i)|*2^(2^i).Terms a(0) =2a(1) =4a(2) =20a(3) =312a(4) =67272a(5) =4295632512External referencesoeis: A059588