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 A253597 #37 Feb 12 2015 22:15:40
%S A253597 399,935,399,935,2015,935,399,4991,51359,2015,1584599,20705,5719,
%T A253597 18095,2915,46079,162687,22847,46079,16719263,12719,7055,80189,104663,
%U A253597 20705,482143,196559,60059,90287,162687,3441239,13971671
%N A253597 Least Lucas-Carmichael number divisible by the n-th prime.
%C A253597 Has any odd prime number at least one Lucas-Carmichael multiple?
%H A253597 Tim Johannes Ohrtmann and Charles R Greathouse IV, <a href="/A253597/b253597.txt">Table of n, a(n) for n = 2..1000</a> (terms up to 202 from Ohrtmann)
%F A253597 a(n) >> n^2 log^2 n. - _Charles R Greathouse IV_, Feb 03 2015
%e A253597 a(2) = 399 because this is the least Lucas-Carmichael number which is divisible by 3 (the second prime number).
%t A253597 LucasCarmichaelQ[n_] := Block[{fi = FactorInteger@ n}, !PrimeQ@ n && Times @@ (Last@# & /@ fi) == 1 && Plus @@ Mod[n + 1, 1 + First@# & /@ fi] == 0]; f[n_] := Block[{k = p = Prime@ n}, While[ !LucasCarmichaelQ@ k, k += p]; k]; Array[f, 35, 2] (* _Robert G. Wilson v_, Feb 11 2015 *)
%o A253597 (PARI) is_A006972(n)=my(f=factor(n)); for(i=1, #f[, 1], if((n+1)%(f[i, 1]+1) || f[i, 2]>1, return(0))); #f[, 1]>1
%o A253597 a(n) = pn = prime(n); ln = 1; until (is_A006972(ln) && (ln % pn == 0), ln++); ln;
%o A253597 (PARI) is_A006972(n)=my(f=factor(n)); for(i=1, #f~, if((n+1)%(f[i, 1]+1) || f[i, 2]>1, return(0))); #f~>1
%o A253597 a(n)=my(p=prime(n), c=p^2+p, t=p); while(!is_A006972(t+=c),); t \\ _Charles R Greathouse IV_, Feb 03 2015
%Y A253597 Cf. A006972, A065091, A253598.
%K A253597 nonn
%O A253597 2,1
%A A253597 _Tim Johannes Ohrtmann_, Jan 05 2015