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 A230498 #18 Aug 03 2023 03:45:55
%S A230498 13,21,21,47,265,607,883,883,883,883,10865,10865,58241,58241,58241,
%T A230498 75781,367815,766165,2931371,5288671,5288671,14838843,14838843,
%U A230498 14838843,33417397,737812313,2774333869,3513898753,3513898753,3513898753,14369883465,14369883465,22865025261
%N A230498 a(n) is the minimal odd odious k>1, such that k^i, i=2,...,n, all are evil, and a(n)=0, if there is no such k.
%C A230498 A conjugate sequence to A230495 and A230496.
%C A230498 Conjecture: For all n, a(n) > 0.
%H A230498 Amiram Eldar, <a href="/A230498/b230498.txt">Table of n, a(n) for n = 2..39</a>
%t A230498 evQ[n_] := EvenQ[DigitCount[n, 2, 1]]; evExp[n_] := Module[{e = 1, p = n^2}, If[! evQ[n], While[evQ[p], p *= n; e++]]; e]; seq[nmax_] := Module[{e, emax = 1, n = 3, s = {}}, Do[e = evExp[n]; If[e > emax, s = Join[s, ConstantArray[n, e - emax]]; emax = e], {n, 3, nmax, 2}]; s]; seq[11000] (* _Amiram Eldar_, Aug 03 2023 *)
%Y A230498 Cf. A000069, A001969, A230494, A230495, A230496, A230497.
%K A230498 nonn,base
%O A230498 2,1
%A A230498 _Vladimir Shevelev_ and _Peter J. C. Moses_, Oct 21 2013
%E A230498 a(27)-a(34) from _Amiram Eldar_, Aug 03 2023