Four-fold convolution of Bell numbers with themselves.

Terms

a(0) =1a(1) =4a(2) =14a(3) =48a(4) =169a(5) =624a(6) =2442a(7) =10188a(8) =45452a(9) =217100a(10) =1109914a(11) =6064584a(12) =35330715a(13) =218788432a(14) =1435302930a(15) =9940062428a(16) =72422364227a(17) =553338786504