Minimum number k for which the digital sum of k*n is 4*n.

Terms

a(0) =0a(1) =4a(2) =4a(3) =13a(4) =22a(5) =139a(6) =133a(7) =427a(8) =1111a(9) =1111a(10) =49999a(11) =40909a(12) =49999a(13) =69223a(14) =357142a(15) =1333333a(16) =3124993a(17) =4705294a(18) =11111111a(19) =31578421a(20) =499999999a(21) =238047619a(22) =409090909a(23) =2169565213a(24) =4166666662a(25) =31999999999a(26) =26923076923a(27) =37037037037a(28) =285713928571a(29) =344824137931