Stirling numbers of the second kind, S(n,4).

Terms

a(0) =1a(1) =10a(2) =65a(3) =350a(4) =1701a(5) =7770a(6) =34105a(7) =145750a(8) =611501a(9) =2532530a(10) =10391745a(11) =42355950a(12) =171798901a(13) =694337290a(14) =2798806985a(15) =11259666950a(16) =45232115901a(17) =181509070050a(18) =727778623825