If 110112011301⋯⋯·1n-101=17801 then the inverse of  1n01 is

Multiplying we get 11+2+3+⋯+n01=17801                           =1n(n-1)201  =17801   given ⇒n(n-1)2=78⇒n=13∴Inverse of 11301 =1−1301