Sum over all complete compositions of n of the element set cardinality.

Terms

a(0) =0a(1) =1a(2) =1a(3) =5a(4) =7a(5) =15a(6) =41a(7) =77a(8) =161a(9) =325a(10) =727a(11) =1460a(12) =3058a(13) =6228a(14) =12815a(15) =26447a(16) =54099a(17) =110800a(18) =226247a(19) =461531a(20) =939678a(21) =1914189a(22) =3890279a(23) =7905962a(24) =16045367a(25) =32550830a(26) =65971827a(27) =133645098a(28) =270561031a(29) =547468214