a(n) = Sum_{k=0..n} binomial(n, k)*CT(n, k) = Sum_{k=0..n} (-1)^(n-k)*binomial(n, k)*CT(n, k), where CT(n, k) is the Catalan triangle A053121.

A344500

a(n) = Sum_{k=0..n} binomial(n, k)*CT(n, k) = Sum_{k=0..n} (-1)^(n-k)*binomial(n, k)*CT(n, k), where CT(n, k) is the Catalan triangle A053121.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =7a(4) =21a(5) =66a(6) =216a(7) =715a(8) =2395a(9) =8101a(10) =27598a(11) =94568a(12) =325612a(13) =1125632a(14) =3904512a(15) =13583195a(16) =47373255a(17) =165585883a(18) =579907758a(19) =2034443127a(20) =7148313381a(21) =25151582046a(22) =88607951512a(23) =312518438532

External references