A130851 Catalan numbers A000108(n) modulo 9.

1, 1, 2, 5, 5, 6, 6, 6, 8, 2, 2, 7, 4, 4, 0, 0, 0, 6, 6, 6, 3, 3, 3, 0, 0, 0, 8, 2, 2, 4, 1, 1, 3, 3, 3, 1, 7, 7, 2, 5, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 6, 6, 3, 3, 3, 0, 0, 0, 3, 3, 3, 6, 6, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 2, 2, 4, 1, 1, 3, 3, 3, 7, 4, 4, 5, 8, 8, 0, 0, 0, 3, 3, 3, 6, 6, 6, 0

Offset: 0

Author

N. J. A. Sloane, Aug 21 2007

Keywords

• nonn
• easy
• base

Crossrefs

Cf. A000108, A010888, A130856.

Programs

Mathematica

Mod[CatalanNumber[Range[0,120]],9] (* Harvey P. Dale, Feb 20 2018 *)

Formula

a(n) = A000108(n) mod 9. - Philippe Deléham, Apr 28 2009

Extensions

Name corrected by Nathaniel Johnston, May 05 2011