Largest proper divisor of the Catalan number A000108(n).

Terms

a(0) =1a(1) =1a(2) =7a(3) =21a(4) =66a(5) =143a(6) =715a(7) =2431a(8) =8398a(9) =29393a(10) =104006a(11) =371450a(12) =1337220a(13) =3231615a(14) =17678835a(15) =64822395a(16) =238819350a(17) =883631595a(18) =3282060210a(19) =12233133510a(20) =45741281820a(21) =171529806825a(22) =644952073662