A sequence generated from the Narayana triangle considered as a matrix, or from Pascal's triangle.

Terms

a(0) =1a(1) =42a(2) =303a(3) =1144a(4) =3105a(5) =6906a(6) =13447a(7) =23808a(8) =39249a(9) =61210a(10) =91311a(11) =131352a(12) =183313a(13) =249354a(14) =331815a(15) =433216a(16) =556257a(17) =703818a(18) =878959a(19) =1084920a(20) =1325121a(21) =1603162a(22) =1922823a(23) =2288064a(24) =2703025a(25) =3172026a(26) =3699567a(27) =4290328a(28) =4949169a(29) =5681130