1,1

R. P. Stanley and Eric Weisstein Catalan Number

Sum of all 1-digit Catalan numbers is 9.

Sum of all 2-digit Catalan numbers is 56.

Sum of all 3-digit Catalan numbers is 561.

Cf. A000108.

Sequence in context: A034362 A037711 A037613 this_sequence A140891 A086888 A064838

Adjacent sequences: A131465 A131466 A131467 this_sequence A131469 A131470 A131471

nonn,base

Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Oct 01 2007