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 A308070 #18 May 19 2019 19:44:40 %S A308070 0,1,2,3,4,5,6,102616333034,102620103253,103055445560,206154633166, %T A308070 206154633200,212216263215,212220033434,315315450515,321340554340, %U A308070 424436332033,424440102253,430461435550,430501403606,533560623156,533600556144 %N A308070 Numbers k such that k is the substring identical to the most significant digits of its base-7 representation. %C A308070 Numbers k whose base-7 representation begins with the same digits as k itself. %H A308070 Scott R. Shannon, <a href="/A308070/b308070.txt">Table of n, a(n) for n = 1..500</a> %e A308070 102616333034_10 = 10261633303415_7, which also begins with '102616333034'. %o A308070 (PARI) isok(n) = my(vb=digits(n, 7), vd=digits(n)); vd == vector(#vd, k, vb[k]); \\ _Michel Marcus_, May 17 2019 %Y A308070 This is a subsequence of A228050. %Y A308070 See A181929, A307254, A307255, A307256, A307257, A308071, A308072 for other bases. %K A308070 nonn,base %O A308070 1,3 %A A308070 _Scott R. Shannon_, May 11 2019