Apply (1+Shift) to Bell numbers.

Terms

a(0) =1a(1) =2a(2) =3a(3) =7a(4) =20a(5) =67a(6) =255a(7) =1080a(8) =5017a(9) =25287a(10) =137122a(11) =794545a(12) =4892167a(13) =31858034a(14) =218543759a(15) =1573857867a(16) =11863100692a(17) =93345011951a(18) =764941675963