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 A217002 #17 Sep 08 2022 05:13:39 %S A217002 139501439,196377335,206238815,239875559,287432495,336545495, %T A217002 353107799,381626399,394426655,406335215,461829599,464972255, %U A217002 577901519,592557119,649351295,653067359,674628479,761212655,775931519,777724415,929892095,993625919,1073352959 %N A217002 Lucas-Carmichael numbers with 6 prime factors. %H A217002 Daniel Suteu, <a href="/A217002/b217002.txt">Table of n, a(n) for n = 1..9382</a> (first 1000 terms from Donovan Johnson) %e A217002 A006972(385) = 139501439 = 7*11*17*19*71*79. %o A217002 (PARI) upto(n, k=6) = my(A=vecprod(primes(k+1))\2, B=n); (f(m, l, p, k, u=0, v=0) = my(list=List()); if(k==1, forprime(p=u, v, my(t=m*p); if((t+1)%l == 0 && (t+1)%(p+1) == 0, listput(list, t))), forprime(q = p, sqrtnint(B\m, k), my(t = m*q); my(L=lcm(l, q+1)); if(gcd(L, t) == 1, my(u=ceil(A/t), v=B\t); if(u <= v, my(r=nextprime(q+1)); if(k==2 && r>u, u=r); list=concat(list, f(t, L, r, k-1, u, v)))))); list); vecsort(Vec(f(1, 1, 3, k))); \\ _Daniel Suteu_, Sep 03 2022 %Y A217002 Cf. A006972 (Lucas-Carmichael numbers), A216925, A216926, A216927, A217003, A217091. %K A217002 nonn %O A217002 1,1 %A A217002 _Donovan Johnson_, Sep 22 2012