This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A328375 #27 Oct 26 2019 22:18:16
%S A328375 24,40,75,152,166,179,181,191,194,199,214,230,235,260,282,296,304,311,
%T A328375 317,323,326,332,342,345,363,370,374,390,417,424,426,443,455,468,471,
%U A328375 474,475,483,489,490,505,512,523,524,536,540,559,567,581,584,585,588,593
%N A328375 Numbers k such that the decimal expansion of 2^k contains the substring 777.
%C A328375 The decimal expansion of 2^k ends in 7776 iff k == 40 (mod 500), so the sequence is infinite. - _Jon E. Schoenfield_, Oct 14 2019
%C A328375 Conjecture: if n > 30536, then a(n) = n + 3623. - _Chai Wah Wu_, Oct 26 2019
%H A328375 Chai Wah Wu, <a href="/A328375/b328375.txt">Table of n, a(n) for n = 1..10000</a>
%e A328375 16777216 = 2^24.
%p A328375 q:= n-> searchtext("777", cat(2^n))>0:
%p A328375 select(q, [$1..600])[]; # _Alois P. Heinz_, Oct 26 2019
%t A328375 aQ[n_] := SequenceCount[IntegerDigits[2^n], {7, 7, 7}] > 0; Select[Range[660], aQ] (* _Amiram Eldar_, Oct 26 2019 *)
%o A328375 (Python)
%o A328375 A328375_list = [k for k in range(1000) if '777' in str(2**k)] # _Chai Wah Wu_, Oct 26 2019
%Y A328375 Cf. A007356 (contains 666), A030000 (contains n).
%K A328375 nonn,easy,base
%O A328375 1,1
%A A328375 _Eder Vanzei_, Oct 14 2019