The Riordan square of the little Schröder numbers A001003.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =4a(5) =1a(6) =11a(7) =17a(8) =7a(9) =1a(10) =45a(11) =76a(12) =40a(13) =10a(14) =1a(15) =197a(16) =353a(17) =216a(18) =72a(19) =13a(20) =1a(21) =903a(22) =1688a(23) =1145a(24) =458a(25) =113a(26) =16a(27) =1a(28) =4279a(29) =8257