a(n) = f(n,n+5) where f is given in A034261.

Terms

a(0) =0a(1) =1a(2) =17a(3) =154a(4) =1066a(5) =6370a(6) =34748a(7) =178296a(8) =875976a(9) =4167669a(10) =19348175a(11) =88112310a(12) =395137470a(13) =1749894510a(14) =7669512840a(15) =33323053200a(16) =143720109360a(17) =615950596170