Number of sets of nonempty words with a total of n letters over binary alphabet such that all letters occur at least once in the set.

A320203

Number of sets of nonempty words with a total of n letters over binary alphabet such that all letters occur at least once in the set.

Terms

    a(0) =3a(1) =12a(2) =38a(3) =110a(4) =302a(5) =806a(6) =2109a(7) =5450a(8) =13917a(9) =35224a(10) =88464a(11) =220608a(12) =546734a(13) =1347290a(14) =3302716a(15) =8057268a(16) =19568800a(17) =47329156a(18) =114025658a(19) =273709580a(20) =654765164a(21) =1561257760a(22) =3711372761a(23) =8797021430a(24) =20794198251a(25) =49024480496a(26) =115292809466a(27) =270495295124a(28) =633186396954

External references