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 A092675 #20 Jul 08 2021 06:20:38
%S A092675 881,8888888888888888881,
%T A092675 8888888888888888888888888888888888888888888888888888888888888888888888888888881
%N A092675 Primes of the form 80*R_k + 1, where R_k is the repunit (A002275) of length k.
%C A092675 Primes of the form 888...881.
%C A092675 The number of 8's in each term is given by the corresponding term of A056664 and so the first term too large to include above is 888...8881 (with 138 8's).
%C A092675 Primes of the form (8*10^k - 71)/9. - _Vincenzo Librandi_, Nov 16 2010
%H A092675 Makoto Kamada, <a href="https://stdkmd.net/nrr/8/88881.htm#prime">Prime numbers of the form 88...881</a>.
%H A092675 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>
%t A092675 Select[Table[10 FromDigits[PadRight[{},n,8]]+1,{n,150}],PrimeQ] (* _Harvey P. Dale_, Aug 07 2019 *)
%Y A092675 Cf. A056664 (corresponding k).
%Y A092675 Cf. A051200, A004022, A093176, A093177, A089346, A093174, A092571.
%K A092675 bref,nonn
%O A092675 1,1
%A A092675 _Rick L. Shepherd_, Mar 02 2004