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 A074379 #34 Apr 23 2022 22:58:20
%S A074379 41041,62745,63973,75361,101101,126217,172081,188461,278545,340561,
%T A074379 449065,552721,656601,658801,670033,748657,838201,852841,997633,
%U A074379 1033669,1082809,1569457,1773289,2100901,2113921,2433601,2455921
%N A074379 Carmichael numbers with exactly 4 prime factors.
%C A074379 Original name was: "Super-Carmichael numbers with exactly 4 factors", and a comment explained that the prefix "super" means that the Moebius function (A008683) equals mu(N) = +1 for these. But for squarefree numbers such as Carmichael numbers (A002997), this just means that they have an even number of prime factors, which is trivial if that number is 4.
%C A074379 In the literature there are other definitions of "super-Carmichael numbers", see the McIntosh and Meštrović references, so we prefer not to use this terminology at all.
%H A074379 R. J. Mathar and Amiram Eldar, <a href="/A074379/b074379.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..6042 from R. J. Mathar)
%H A074379 Richard J. McIntosh <a href="https://www.emis.de/journals/INTEGERS/papers/o59/o59.Abstract.html">Carmichael numbers with (p + 1) | (n - 1)</a>, Integers 14 (2014) #A59.
%H A074379 Romeo Meštrović, <a href="https://arxiv.org/abs/1305.1867">Generalizations of Carmichael numbers I</a>, arXiv:1305.1867, May 04 2013
%F A074379 Intersection of A002997 (Carmichael numbers) and A046386 (product of four distinct primes). - _M. F. Hasler_, Mar 24 2022
%e A074379 41041 = 7 * 11 * 13 * 41.
%e A074379 62745 = 3 * 5 * 47 * 89.
%t A074379 p = Table[ Prime[i], {i, 1, 10}]; f[n_] := Union[ PowerMod[ Select[p, GCD[ #, n] == 1 & ], n - 1, n]]; Select[ Range[2500000], !PrimeQ[ # ] && OddQ[ # ] && Length[ FactorInteger[ # ]] == 4 && MoebiusMu[ # ] == 1 && f[ # ] == {1} & ]
%o A074379 (PARI) is_A074379(n)=is_A002997(n) && is_A046386(n) \\ _M. F. Hasler_, Mar 24 2022
%o A074379 (PARI) list(lim)=my(v=List()); forprime(p=3,sqrtnint(lim\=1,4), forprime(q=p+2,sqrtnint(lim\p,3), if(q%p==1, next); forprime(r=q+2,sqrtint(lim\p\q), if(r%p==1 || r%q==1, next); my(m=lcm([p-1,q-1,r-1]),pqr=p*q*r,t=Mod(1,m)/pqr,L=lim\pqr); fordiv(pqr-1,d, my(s=d+1); if(s>L, break); if(s==t && s>r && isprime(s), listput(v,pqr*s)))))); Set(v) \\ _Charles R Greathouse IV_, Apr 23 2022
%Y A074379 Cf. A002997 (Carmichael numbers), A006931 (least Carmichael with n prime factors), A046386 (products of four distinct primes).
%K A074379 nonn
%O A074379 1,1
%A A074379 _Jani Melik_, Sep 24 2002
%E A074379 Edited and extended by _Robert G. Wilson v_, Oct 03 2002
%E A074379 Edited by _M. F. Hasler_, Mar 24 2022