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 A074380 #11 Sep 01 2016 10:25:22
%S A074380 561,645,1105,1729,1905,2465,2821,4371,6601,8481,8911,10585,12801,
%T A074380 13741,13981,15841,16705,25761,29341,30121,30889,33153,34945,41665,
%U A074380 46657,52633,57421,68101,74665,83665,87249,88561,91001,93961,113201
%N A074380 Sarrus numbers n (A001567) which satisfy mu(n) = -1 and which are not Super-Poulet numbers (A050217).
%C A074380 Some of these are Carmichael numbers, A002997: 561, 1105, 1729, ....
%H A074380 Charles R Greathouse IV, <a href="/A074380/b074380.txt">Table of n, a(n) for n = 1..10000</a>
%t A074380 Select[ Range[115000], !PrimeQ[ # ] && OddQ[ # ] && PowerMod[2, # - 1, # ] == 1 && Union[ PowerMod[2, Drop[Divisors[ # ], 1], # ]] != {2} && MoebiusMu[ # ] != 1 &]
%o A074380 (PARI) is(n)=if(isprime(n) || Mod(2,n)^(n-1)!=1 || moebius(n)>=0, return(0)); fordiv(n, d, if(Mod(2, d)^d!=2, return(1))); 0 \\ _Charles R Greathouse IV_, Sep 01 2016
%Y A074380 Cf. A001567, A050217, A002997.
%K A074380 nonn
%O A074380 1,1
%A A074380 _Jani Melik_, Sep 24 2002
%E A074380 Edited and extended by _Robert G. Wilson v_, Oct 03 2002