a(n) is the denominator of Catalan-Daehee number d(n).

Terms

a(0) =1a(1) =1a(2) =3a(3) =3a(4) =15a(5) =5a(6) =105a(7) =105a(8) =63a(9) =315a(10) =3465a(11) =495a(12) =6435a(13) =9009a(14) =15015a(15) =15015a(16) =255255a(17) =23205a(18) =37791a(19) =188955a(20) =101745a(21) =1119195a(22) =25741485a(23) =572033a(24) =42902475a(25) =79676025a(26) =42181425a(27) =42181425a(28) =155687805a(29) =40970475