Number of permutations in S_n with longest increasing subsequence of length <= 4.
A047889
Number of permutations in S_n with longest increasing subsequence of length <= 4.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =119a(6) =694a(7) =4582a(8) =33324a(9) =261808a(10) =2190688a(11) =19318688a(12) =178108704a(13) =1705985883a(14) =16891621166a(15) =172188608886
External references
- oeis: A047889