Nearest integer to Gamma(n + 4/7)/Gamma(4/7).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =8a(5) =38a(6) =210a(7) =1380a(8) =10450a(9) =89574a(10) =857352a(11) =9063435a(12) =104876887a(13) =1318452295a(14) =17893281148a(15) =260730668151