Partial sums of (Catalan numbers starting 1, 2, 5, ...).

Terms

a(0) =0a(1) =1a(2) =3a(3) =8a(4) =22a(5) =64a(6) =196a(7) =625a(8) =2055a(9) =6917a(10) =23713a(11) =82499a(12) =290511a(13) =1033411a(14) =3707851a(15) =13402696a(16) =48760366a(17) =178405156a(18) =656043856a(19) =2423307046a(20) =8987427466a(21) =33453694486a(22) =124936258126a(23) =467995871776