Sum of all entries in character table of the symmetric group S_n.

Terms

a(0) =1a(1) =2a(2) =5a(3) =13a(4) =31a(5) =89a(6) =259a(7) =842a(8) =2810a(9) =10020a(10) =37266a(11) =145373a(12) =586071a(13) =2453927a(14) =10590180a(15) =47159351a(16) =215706629a(17) =1013916313a(18) =4882544468a(19) =24087770591a(20) =121481296510a(21) =626169893024