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 A230746 #15 Feb 16 2025 08:33:20
%S A230746 68154001,3713287801,63593140801,122666876401,193403531401,
%T A230746 227959335001,246682590001,910355497801,4790779641001,5367929037001,
%U A230746 6486222838801,24572944746001,25408177226401,27134994772801,55003376283001,63926508701401,108117809748001,112614220996801
%N A230746 Carmichael numbers of the form (30*k + 1)*(120*k + 1)*(150*k + 1), where 30*k + 1, 120*k + 1 and 150*k + 1 are all primes.
%H A230746 Amiram Eldar, <a href="/A230746/b230746.txt">Table of n, a(n) for n = 1..10000</a>
%H A230746 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CarmichaelNumber.html">Carmichael Number</a>
%H A230746 <a href="/index/Ca#Carmichael">Index entries for sequences related to Carmichael numbers</a>
%H A230746 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%F A230746 (A007304 INTERSECT A157956) INTERSECT A230722.
%t A230746 carmQ[n_] := CompositeQ[n] && Divisible[n - 1, CarmichaelLambda[n]]; v = {30, 120, 150}; Times @@ (v*# + 1) & /@ Select[Range[1000], AllTrue[(w = v*# + 1), PrimeQ] && carmQ[Times @@ w] &] (* _Amiram Eldar_, Nov 11 2019 *)
%o A230746 (Magma) [n : k in [1..593 by 2] | IsPrime(a) and IsPrime(b) and IsPrime(c) and IsOne(n mod CarmichaelLambda(n)) where n is a*b*c where a is 30*k+1 where b is 120*k+1 where c is 150*k+1]
%Y A230746 Subsequence of A083739 and of A230722.
%Y A230746 Cf. A002997, A007304, A157956.
%K A230746 nonn
%O A230746 1,1
%A A230746 _Arkadiusz Wesolowski_, Oct 29 2013