A067468 Numbers n such that 7 is the first digit of 7^n.
1, 20, 33, 46, 59, 72, 104, 117, 130, 143, 175, 188, 201, 214, 246, 259, 272, 285, 317, 330, 343, 356, 388, 401, 414, 427, 459, 472, 485, 498, 511, 530, 543, 556, 569, 582, 614, 627, 640, 653, 685, 698, 711, 724, 756, 769, 782, 795, 827, 840, 853, 866, 898
Offset: 1
Crossrefs
Cf. A067485.
Programs
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Mathematica
Select[Range[1000],IntegerDigits[7^#][[1]]==7&] (* Harvey P. Dale, Aug 04 2023 *)
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PARI
for(n=1,1000, if(floor(7^n/10^(floor(n*log(7)/log(10))))==7,print1(n,",")))