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 A089195 #28 Jan 18 2025 09:06:47
%S A089195 2,5,37,101,197,677,4357,5477,8837,12101,16901,17957,21317,28901,
%T A089195 42437,44101,52901,98597,106277,148997,164837,184901,217157,220901,
%U A089195 224677,324901,401957,417317,427717,454277,476101,509797,682277,792101,820837
%N A089195 Primes p such that all prime factors of p-1 have exponent 2.
%C A089195 This property for prime p-1 = cube only numbers does not hold since the sum of 2 cubes has factors and p-1 = q^3 => p = q^3+1 = sum of 2 cubes.
%H A089195 Amiram Eldar, <a href="/A089195/b089195.txt">Table of n, a(n) for n = 1..10000</a> (terms 2..301 from Vincenzo Librandi)
%e A089195 101 is included because 100 = 2^2*5^2 only square factors. 109 is not because while 108=2^2*3^3 has a square only factor it also has a cube factor.
%t A089195 Prepend[Select[Table[Prime[n],{n,70000}],Length[Union[Last/@FactorInteger[#-1]]]==1&&Union[Last/@FactorInteger[#-1]]=={2}&], 2] (* _Vladimir Joseph Stephan Orlovsky_, Apr 08 2011 *)
%t A089195 seq[lim_] := Select[Select[Range[Floor[Surd[lim-1, 2]]], SquareFreeQ]^2 + 1, PrimeQ]; seq[10^6] (* _Amiram Eldar_, Jan 18 2025 *)
%o A089195 (PARI) list(lim) = select(isprime, apply(x -> x^2 + 1, select(issquarefree, vector(sqrtnint(lim-1, 2), i, i)))); \\ _Amiram Eldar_, Jan 18 2025
%Y A089195 Cf. A188764, A188717.
%K A089195 easy,nonn
%O A089195 1,1
%A A089195 _Cino Hilliard_, Dec 08 2003
%E A089195 a(1) = 2 inserted by _Amiram Eldar_, Jan 18 2025