Number of subsets of {1..n} such that it is not possible to choose a different prime factor of each element.

A370583

Number of subsets of {1..n} such that it is not possible to choose a different prime factor of each element.

Terms

    a(0) =0a(1) =1a(2) =2a(3) =4a(4) =10a(5) =20a(6) =44a(7) =88a(8) =204a(9) =440a(10) =908a(11) =1816a(12) =3776a(13) =7552a(14) =15364a(15) =31240a(16) =63744a(17) =127488a(18) =257592a(19) =515184a(20) =1036336a(21) =2079312a(22) =4166408a(23) =8332816a(24) =16709632a(25) =33470464a(26) =66978208a(27) =134067488a(28) =268236928a(29) =536473856

External references