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 A377884 #26 Dec 12 2024 23:32:55
%S A377884 25,49,77,91,119,121,133,143,161,169,187,203,209,221,247,253,289,299,
%T A377884 319,323,341,361,377,391,403,407,437,451,473,481,493,517,527,529,533,
%U A377884 551,559,583,589,611,629,649,667,671,689,697,703,713,731,737,767,779,781,793,799
%N A377884 Composite numbers k without prime factors that are divisors of the greatest primorial less than k.
%e A377884 The greatest primorial below 25 is 6, the factors of which are 2 and 3, neither of which are factors of 25=5^2.
%t A377884 q[k_] := Module[{p = 2, r = 2}, If[CompositeQ[k], While[r < k && ! Divisible[k, p], p = NextPrime[p]; r *= p]; r >= k, False]]; Select[Range[800], q] (* _Amiram Eldar_, Nov 14 2024 *)
%o A377884 (PARI) P(n)=my(t=1, k); forprime(p=2, , k=t*p; if(k>n, return(t), t=k)); \\ A260188
%o A377884 isok(k) = (k>1) && !isprime(k) && (gcd(k, P(k-1)) == 1); \\ _Michel Marcus_, Nov 12 2024
%Y A377884 Intersection of A002808 and A335284.
%Y A377884 Cf. A002110, A260188.
%K A377884 nonn
%O A377884 1,1
%A A377884 _Daniel D Gibson_, Nov 10 2024