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 A060262 #11 Oct 03 2021 04:45:42
%S A060262 4,17,55,7,93,754,2611,31092,55207,301252,955428,805428,3651249,
%T A060262 3686621,5510710,42337888,109670084,590903433,1010572448
%N A060262 a(n) is the smallest k such that prime(k), prime(k+1), ..., prime(k+n-1) all have 10 as a primitive root, but prime(k-1) and prime(k+n) do not.
%C A060262 A prime p has 10 as a primitive root iff the length of the period of the decimal expansion of 1/p is p-1.
%C A060262 a(21) = 9774718453 and a(23) = 9525468065. - _Amiram Eldar_, Oct 03 2021
%t A060262 test[p_] := MultiplicativeOrder[10, p]===p-1; For[n=1, n<100, n++, a[n]=0]; v=4; While[True, For[n=1, test[Prime[v+n]], n++, Null]; If[a[n]==0, a[n]=v; Print["a(", n, ") = ", v]]; For[v+=n+1, !test[Prime[v]], v++, Null]]
%Y A060262 Cf. A001913, A002371, A060259, A060260, A060261.
%K A060262 nonn,more
%O A060262 1,1
%A A060262 _Jeff Burch_, Mar 23 2001
%E A060262 Edited by _Dean Hickerson_, Jun 17 2002
%E A060262 a(13)-a(19) from _Amiram Eldar_, Oct 03 2021