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 A044240 #18 Sep 03 2025 09:08:01 %S A044240 53,117,181,245,309,373,424,437,501,565,629,693,757,821,885,936,949, %T A044240 1013,1077,1141,1205,1269,1333,1397,1448,1461,1525,1589,1653,1717, %U A044240 1781,1845,1909,1960,1973,2037,2101,2165,2229,2293,2357 %N A044240 Numbers k such that string 6,5 occurs in the base 8 representation of k but not of k-1. %H A044240 Paolo Xausa, <a href="/A044240/b044240.txt">Table of n, a(n) for n = 1..10000</a> %t A044240 A044240Q[k_] := StringContainsQ[IntegerString[k, 8], "65"] && StringFreeQ[IntegerString[k - 1, 8], "65"]; %t A044240 Select[Range[5000], A044240Q] (* _Paolo Xausa_, Sep 03 2025 *) %Y A044240 Cf. A007094. %K A044240 nonn,base,changed %O A044240 1,1 %A A044240 _Clark Kimberling_