A131810 Additive persistence of Catalan numbers.

0, 0, 0, 0, 1, 1, 1, 2, 1, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 2, 2, 2, 3, 2, 3, 2, 2, 2, 3, 3, 2, 2, 2, 3, 2, 4, 3, 2, 3

Offset: 0

Author

Paolo P. Lava and Giorgio Balzarotti, Jul 18 2007

Keywords

• easy
• nonn
• base

Examples

			Catalan number 429 -> 4+2+9=15 -> 1+5=6 thus persistence is 2
		

Crossrefs

Cf. A003001, A006050, A000108, A131809.

Programs

Maple

with(numtheory): with(combinat): P:=proc(n) local a,t; t:=0; a:=(2*n)!/(n!*(n+1)!); while a>9 do t:=t+1; a:=convert(convert(a,base,10),`+`); od; t;
end: seq(P(i),i=0..10^2);

Extensions

Corrected entries and Maple code by Paolo P. Lava, Dec 19 2017