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 A292021 #17 Aug 26 2023 04:17:43
%S A292021 20705,80189,120581,1162349,7274249,8734109,10260809,14658349,
%T A292021 49412285,90393029,105818129,110066669,125532329,256074029,362868329,
%U A292021 366648281,395032609,434886605,503733257,558705449,563601257,574342145,640057109,939989609,962529749
%N A292021 Lucas-Carmichael numbers that are congruent to 1 (mod 4).
%C A292021 Most Lucas-Carmichael numbers are congruent to 3 (mod 4). Of the 9967 numbers less than 10^12 only 198 are congruent to 1 (mod 4).
%C A292021 Analogous to A185321 - Carmichael numbers that are congruent to 3 (mod 4).
%H A292021 Amiram Eldar, <a href="/A292021/b292021.txt">Table of n, a(n) for n = 1..198</a> (terms below 10^12)
%t A292021 a=Select[Range[2, 10^6],!PrimeQ[#] && Union[Transpose[FactorInteger[#]][[2]]] == {1} && Union[Mod[# + 1, Transpose[FactorInteger[#]][[1]] + 1]]=={0} &] ;Select[a,Mod[#,4]==1 &] (* after _Richard Pinch_ and _Jeffrey Shallit_ at A006972 *)
%Y A292021 Intersection of A006972 and A016813.
%Y A292021 Cf. A110885, A185321.
%K A292021 nonn
%O A292021 1,1
%A A292021 _Amiram Eldar_, Sep 07 2017