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 A262055 #32 Aug 25 2019 05:57:44
%S A262055 9,21,65,105,133,273,341,481,511,561,585,1001,1105,1281,1417,1541,
%T A262055 1661,1729,1905,2047,2465,2501,3201,3277,3641,4033,4097,4641,4681,
%U A262055 4921,5461,6305,6533,6601,7161,8321,8481,9265,9709,10261,10585,10745,11041,12545
%N A262055 Euler pseudoprimes to base 8: composite integers such that abs(8^((n - 1)/2)) == 1 mod n.
%H A262055 Amiram Eldar, <a href="/A262055/b262055.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..182 from Daniel Lignon)
%t A262055 eulerPseudoQ[n_?PrimeQ, b_] = False; eulerPseudoQ[n_, b_] := Block[{p = PowerMod[b, (n - 1)/2, n]}, p == Mod[1, n] || p == Mod[-1, n]]; Select[2 Range[11000] + 1, eulerPseudoQ[#, 8] &] (* _Michael De Vlieger_, Sep 09 2015, after _Jean-François Alcover_ at A006970 *)
%o A262055 (PARI) for(n=1, 1e5, if( Mod(8, (2*n+1))^n == 1 || Mod(8, (2*n+1))^n == 2*n && bigomega(2*n+1) != 1 , print1(2*n+1", "))); \\ _Altug Alkan_, Oct 11 2015
%Y A262055 Cf. A006970 (base 2), A262051 (base 3), A262052 (base 5), A262053 (base 6), A262054 (base 7), this sequence (base 8).
%K A262055 nonn
%O A262055 1,1
%A A262055 _Daniel Lignon_, Sep 09 2015