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 A175734 #29 Sep 08 2022 08:45:51
%S A175734 9,49,961,9409,97969,994009,9840769,99460729,999002449,9998200081,
%T A175734 99996985729,999966000289,9999995824729,99999820000081,
%U A175734 999997874844049,9999997800000121,99999977853408361,999999874000003969,9999999828172082689,99999999340000001089
%N A175734 Largest n-digit number with 3 divisors.
%C A175734 Because every number with exactly three divisors must be the square of a prime, the last digit of each term in this sequence is either 1 or 9. - _Harvey P. Dale_, Aug 18 2011 [with thanks to _Ant King_ and _Christopher Hunt Gribble_]
%H A175734 Charles R Greathouse IV, <a href="/A175734/b175734.txt">Table of n, a(n) for n = 1..1000</a>
%F A175734 a(n) = A132153(n)^2.
%t A175734 Join[{9},Table[NextPrime[Sqrt[10^n-1],-1]^2,{n,2,20}]](* _Harvey P. Dale_, Aug 18 2011 *)
%o A175734 (Magma) A175734 := func<n|PreviousPrime(Isqrt(10^n)+1)^2>; // _Jason Kimberley_, Aug 18 2011
%o A175734 (PARI) A175734(n)=precprime(sqrtint(10^n))^2 \\ _M. F. Hasler_, Aug 18 2011
%Y A175734 Cf. A131581, A132153, A136582, A175733.
%K A175734 nonn,base
%O A175734 1,1
%A A175734 _Jaroslav Krizek_, Aug 24 2010
%E A175734 a(14)-a(20) from _Harvey P. Dale_, Aug 18 2011