A152766 Largest proper divisor of the Catalan number A000108(n).

1, 1, 7, 21, 66, 143, 715, 2431, 8398, 29393, 104006, 371450, 1337220, 3231615, 17678835, 64822395, 238819350, 883631595, 3282060210, 12233133510, 45741281820, 171529806825, 644952073662, 2430973200726, 9183676536076, 34766775458002, 131873975875180

Offset: 2

Author

Omar E. Pol, Dec 15 2008

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 2..1669

Crossrefs

Cf. A000108, A152761, A152762, A152763, A152764, A152765.

Programs

Mathematica

Divisors[CatalanNumber[#]][[-2]]&/@Range[2,40] (* Harvey P. Dale, Jun 13 2011 *)

Formula

a(n) = A032742(A000108(n)). - Amiram Eldar, Dec 01 2019

Extensions

Edited and extended by N. J. A. Sloane, Dec 19 2008