7-Modular Catalan Numbers C_{n,7}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =42a(6) =132a(7) =429a(8) =1429a(9) =4851a(10) =16718a(11) =58331a(12) =205632a(13) =731272a(14) =2620176a(15) =9449695a(16) =34276230a(17) =124959485a(18) =457621780a(19) =1682686509a(20) =6209928010a(21) =22993696620a(22) =85396852670a(23) =318034472365