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 A379644 #11 Feb 27 2025 11:16:21
%S A379644 2,3,7,61,3221,37,43,7321,1772893,13421,15797,13,1093,1623931,
%T A379644 195019441,17,50544702849929377,590077,6115909044841454629,212601841,
%U A379644 1723,23,829,10657,3001,53,5559917315850179173,29,523,31,50159,51329,661,71707,211,3138426605161
%N A379644 Smallest primitive prime factor of 11^n-1.
%C A379644 Also, smallest prime p such that 1/p has undecimal period n.
%H A379644 Max Alekseyev, <a href="/A379644/b379644.txt">Table of n, a(n) for n = 1..330</a> (first 253 terms from Sean A. Irvine)
%o A379644 (PARI) listap(nn) = {prf = []; for (n=1, nn, vp = (factor(11^n-1)[, 1])~; f = setminus(Set(vp), Set(prf)); prf = concat(prf, f); print1(vecmin(Vec(f)), ", "); ); }
%Y A379644 Cf. A112927 (base 2), A143663 (base 3), A112092 (base 4), A143665 (base 5), A379639 (base 6), A379640 (base 7), A379641 (base 8), A379642 (base 9), A007138 (base 10), A379644 (base 11), A252170 (base 12).
%Y A379644 Cf. A274910.
%K A379644 nonn
%O A379644 1,1
%A A379644 _Sean A. Irvine_, Dec 28 2024