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 A333131 #12 Mar 09 2020 03:15:10
%S A333131 11500521553,13079177569,52474339009,168003672409,229352039821,
%T A333131 280792563977,318289021201,428178002569,918660756421,2015841188197,
%U A333131 2367478228501,2544457029601,2639665216117,3023595814801,3457449931321,3712164285421,4348114583017,6046196043229
%N A333131 Super pseudoprimes to both bases 2 and 3 (A333130) with more than two prime factors (counted with multiplicity).
%C A333131 Up to 2^64 all the 1085 terms are nonsquarefree, 2 terms have 4 prime factors: a(163) = 18362297383286473 = 3037 * 6073 * 9109 * 109297 and a(651) = 2587580959818925201 = 18121 * 36241 * 54361 * 72481, and no term have more than 4 prime factors.
%H A333131 Amiram Eldar, <a href="/A333131/b333131.txt">Table of n, a(n) for n = 1..1085</a> (terms below 2^64)
%e A333131 11500521553 is a term since it is a Fermat pseudoprime to both bases 2 and 3, and its proper divisors that are larger than 1 are either primes (937, 1873, 6553) or Fermat pseudoprimes to both bases 2 and 3 (1755001, 6140161, 12273769, 11500521553).
%t A333131 pspQ[n_] := PrimeOmega[n] > 2 && AllTrue[Rest @ Divisors[n], PowerMod[2, # - 1, #] == 1 && PowerMod[3, # - 1, #] == 1 &]; seq = {}; Do[If[pspQ[n], AppendTo[seq, n]], {n, 1, 6*10^10}]; seq
%Y A333131 Subsequence of A001567, A005935, A050217, A052155, A153513, A178997, A328662, A328663, A333130.
%K A333131 nonn
%O A333131 1,1
%A A333131 _Amiram Eldar_, Mar 08 2020