Number of ascent sequences of length n with exactly two flat steps.

A242155

Number of ascent sequences of length n with exactly two flat steps.

Terms

    a(0) =1a(1) =3a(2) =12a(3) =50a(4) =240a(5) =1281a(6) =7588a(7) =49392a(8) =350775a(9) =2700115a(10) =22399476a(11) =199258488a(12) =1892343362a(13) =19111149225a(14) =204532683600

External references