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 A325147 #15 Feb 11 2020 02:03:23
%S A325147 10,546,2,46,6630,76670,211659630,6,261870,111418,46,13589784390,
%T A325147 524588442,114,1138240087314330,2,276742830,26805565070,1909802752494,
%U A325147 3210,15370,177430547680928732190,358,5760551069383110,76004922,1126,4347631610092420338,81366
%N A325147 Reduced Clausen numbers.
%C A325147 Let P(m) denote the prime factors of m and C(m) = Clausen(m-1, 1) (cf. A160014) then Product_{p in P(C(m)) setminus P(m)} p is in this sequence provided P(m) is a subset of P(C(m)).
%e A325147 Let n = 561 then P(561) = {3, 11, 17} and P(Clausen(560,1)) = {2, 3, 5, 11, 17, 29, 41, 71, 113, 281}. Since P(561) is a subset of P(Clausen(560, 1)), a(18) = 2*5*29*41*71*113*281 = 26805565070.
%p A325147 with(numtheory): a := proc(n) if isweakCarmichael(n) then # cf. A225498 and A160014
%p A325147 mul(m, m in factorset(Clausen(n-1, 1)) minus factorset(n)) else NULL fi end:
%p A325147 seq(a(n), n=2..1350);
%t A325147 pf[n_] := FactorInteger[n][[All, 1]];
%t A325147 Clausen[0, _] = 1; Clausen[n_, k_] := Times @@ (Select[Divisors[n], PrimeQ[# + k]&] + k);
%t A325147 weakCarmQ[n_] := If[EvenQ[n] || PrimeQ[n], Return[False], pf[n] == (pf[n] ~Intersection~ pf[Clausen[n - 1, 1]])];
%t A325147 f[n_] := Times @@ Complement[pf[Clausen[n - 1, 1]], pf[n]];
%t A325147 f /@ Select[Range[2, 2000], weakCarmQ] (* _Jean-François Alcover_, Jul 21 2019 *)
%Y A325147 Weak Carmichael numbers are A225498. Clausen numbers are in A160014.
%Y A325147 A324977 is a subsequence.
%K A325147 nonn
%O A325147 1,1
%A A325147 _Peter Luschny_, May 21 2019