%I A023425
%S A023425 1,1,1,1,1,2,5,13,34,90,241,652,1780,4899,13581,37893,
%T A023425 106340,299978,850187,2419788,6913658,19822439,
%U A023425 57015620,164476023,475752469,1379553027,4009532279
%N A023425 Generalized Catalan Numbers.
%t A023425 Clear[ a ]; a[ 0 ]=1; a[ n_Integer ] := a[ n ]=a[ n-1 ]+Sum[ a[ k ]*a[ 
               n-k ], {k, 1, n-4} ];
%Y A023425 Cf. A000108, A001006, A004148, A006318.
%Y A023425 Sequence in context: A097417 A006801 A114173 this_sequence A090827 A109192 
               A062465
%Y A023425 Adjacent sequences: A023422 A023423 A023424 this_sequence A023426 A023427 
               A023428
%K A023425 nonn,easy
%O A023425 0,6
%A A023425 Olivier Gerard (olivier.gerard(AT)gmail.com)