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 A084476 #11 Jul 08 2023 11:50:42
%S A084476 0,3,13,43,81,147,73,3,831,49,987,691,183,4153,279,667,709,277,1687,
%T A084476 997,1207,91,1411,393,951,9793,2217,6229,2317,213,399,19,2317,609,
%U A084476 2607,11901,10563,5473,3,5923,17527,8569,16701,11989,9757,6489,3489,2899
%N A084476 Least k such that 10^(2n-1)+k is a brilliant number.
%C A084476 Least brilliant number greater than 10^(2n) is {10^n+A033873(n)}^2. The web site also lists the two prime factors.
%H A084476 Harry Metrebian, <a href="/A084476/b084476.txt">Table of n, a(n) for n = 1..65</a>
%H A084476 Dario Alejandro Alpern, <a href="https://www.alpertron.com.ar/BRILLIANT.HTM">Brilliant numbers</a>
%e A084476 a(3)=13 because 10^5+13 = 100013 = 103*971.
%t A084476 NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; LengthBase10[n_] := Floor[ Log[10, n] + 1]; f[n_] := Block[{k = 0}, If[ EvenQ[n] && n > 1, NextPrim[ 10^(n/2)]^2 - 10^(n/2), While[fi = FactorInteger[10^n + k]; Plus @@ Flatten[ Table[ # [[2]], {1}] & /@ fi] != 2 || Length[ Union[ LengthBase10 /@ Flatten[ Table[ # [[1]], {1}] & /@ fi]]] != 1, k++ ]; k]]; Table[ f[2n + 1], {n, 1, 24}]
%Y A084476 Cf. A078972, A084475.
%K A084476 base,hard,nonn
%O A084476 1,2
%A A084476 _Robert G. Wilson v_, Jun 27 2003