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 A356489 #11 Aug 09 2022 10:56:35
%S A356489 1,1,1,3,5,3,1,3,11,7,15,3,5,21,23,13,29,15,33,35,3,39,41,11,3,5,51,
%T A356489 53,3,7,21,65,17,69,37,15,39,3,83,43,89,15,95,3,7,33,105,111,113,57,
%U A356489 29,119,15,5,1,131,67,15,69,35,141,73,51,155,39,79,165,21,173,87,11,179
%N A356489 a(n) = A000265(rad(prime(n)-1)), rad = A007947.
%H A356489 Michael De Vlieger, <a href="/A356489/b356489.txt">Table of n, a(n) for n = 1..10000</a>
%F A356489 a(n) = A000265(rad(prime(n)-1)) = rad(A000265(prime(n)-1)).
%F A356489 a(n) = Product_{odd primes p dividing prime(n)-1} p.
%F A356489 a(n) = A000265(A077063(n)) = rad(A057023(n)) = A204455(prime(n)-1).
%e A356489 prime(8) = 19, so a(8) = A000265(rad(18)) = A000265(6) = 3.
%e A356489 prime(11) = 31, so a(11) = A000265(rad(30)) = A000265(30) = 15.
%t A356489 Array[#/2^IntegerExponent[#, 2] &[Times @@ FactorInteger[Prime[#] - 1][[All, 1]]] &, 72] (* _Michael De Vlieger_, Aug 09 2022 *)
%o A356489 (PARI) a(n) = factorback(setminus(factorint(prime(n)-1)[, 1]~, [2]))
%Y A356489 Cf. A000265, A007947, A077063, A057023, A204455.
%K A356489 nonn,easy
%O A356489 1,4
%A A356489 _Jianing Song_, Aug 09 2022