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 A353440 #18 Jun 20 2025 18:49:08 %S A353440 7,14,17,19,21,22,23,24,25,26,28,29,31,34,35,38,39,41,43,46,47,49,51, %T A353440 53,56,57,58,59,61,62,65,67,68,69,70,71,76,79,81,83,84,85,86,87,89,92, %U A353440 93,94,95,96,97,98,102,103,104,106,107,109,112,113,114,115,116,117,118 %N A353440 Integers m such that the decimal expansion of 1/m contains the digit 4. %C A353440 If m is a term, 10*m is also a term, so terms with no trailing zeros are all primitive terms. %H A353440 <a href="/index/1#1overn">Index entries for sequences related to decimal expansion of 1/n</a>. %e A353440 m = 14 is a term since 1/14 = 0.0714285714285... %e A353440 m = 22 is a term since 1/22 = 0.04545454545... (here, 4 is the smallest digit). %e A353440 m = 693 is a term since 1/693 = 0.001443001443... (here, 4 is the largest digit). %t A353440 f[n_] := Union[ Flatten[ RealDigits[ 1/n][[1]] ]]; Select[ Range@ 125, MemberQ[f@#, 4] &] %Y A353440 A351470 (largest digit=4) and A352158 (smallest digit=4) are subsequences. %Y A353440 Similar with digit k: A352154 (k=0), A353437 (k=1), A353438 (k=2), A353439 (k=3), this sequence (k=4), A353441 (k=5), A353442 (k=6), A353443 (k=7), A353444 (k=8), A333237 (k=9). %K A353440 nonn,base %O A353440 1,1 %A A353440 _Bernard Schott_ and _Robert G. Wilson v_, Apr 24 2022