Number of permutations of [n+1] with exactly 1 increasing subsequence of length 3.

A003517

Number of permutations of [n+1] with exactly 1 increasing subsequence of length 3.

Terms

    a(0) =1a(1) =6a(2) =27a(3) =110a(4) =429a(5) =1638a(6) =6188a(7) =23256a(8) =87210a(9) =326876a(10) =1225785a(11) =4601610a(12) =17298645a(13) =65132550a(14) =245642760a(15) =927983760a(16) =3511574910a(17) =13309856820a(18) =50528160150a(19) =192113383644a(20) =731508653106

External references