A044121 Numbers n such that string 3,1 occurs in the base 6 representation of n but not of n-1.

19, 55, 91, 114, 127, 163, 199, 235, 271, 307, 330, 343, 379, 415, 451, 487, 523, 546, 559, 595, 631, 667, 684, 739, 762, 775, 811, 847, 883, 919, 955, 978, 991, 1027, 1063, 1099, 1135, 1171, 1194, 1207, 1243, 1279, 1315, 1351