%I #6 Feb 13 2023 11:56:18
%S 4,12,20,28,36,44,52,53,55,57,59,60,72,84,96,108,120,132,144,146,149,
%T 152,155,156,168,180,192,204,216,228,240,242,245,248,251,252,264,276,
%U 288,300,312,324,336,338,341,344,347,348,360
%N Position of n-th 7 in A031057.
%t Position[Table[IntegerDigits[2n-1,8],{n,200}]//Flatten,7]//Flatten (* _Harvey P. Dale_, Feb 13 2023 *)
%K nonn
%O 1,1
%A _Clark Kimberling_