Number of partitions of [n] without prime sized blocks.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =6a(6) =17a(7) =43a(8) =135a(9) =536a(10) =2262a(11) =9109a(12) =40119a(13) =198069a(14) =1057149a(15) =5656915a(16) =31937212a(17) =191032078a(18) =1218669125a(19) =7948119483a(20) =54117500635a(21) =381631039690