Number of matched parentheses and brackets of length n, where a closing bracket will close any remaining open parentheses back to the matching open bracket (as in some versions of LISP).

A078623

Number of matched parentheses and brackets of length n, where a closing bracket will close any remaining open parentheses back to the matching open bracket (as in some versions of LISP).

Terms

    a(0) =1a(1) =0a(2) =2a(3) =1a(4) =9a(5) =11a(6) =56a(7) =106a(8) =421a(9) =1009a(10) =3565a(11) =9736a(12) =32594a(13) =95811a(14) =313535a(15) =961780a(16) =3123577a(17) =9831373a(18) =31915121a(19) =102110314a(20) =332366526a(21) =1075228773a(22) =3513373374a(23) =11456961550a(24) =37590603312a(25) =123327267531a(26) =406246177511

External references