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 A068692 #17 Jul 02 2025 11:30:40
%S A068692 7,89,887,8887,88883,888887,8888861,88888883,888888887,8888888809,
%T A068692 88888888801,888888888887,8888888888849,88888888888889,
%U A068692 888888888888883,8888888888888647,88888888888888889,888888888888888809,8888888888888888881,88888888888888888867,888888888888888888683
%N A068692 Largest n-digit prime with all even digits except for the least significant digit.
%H A068692 Robert Israel, <a href="/A068692/b068692.txt">Table of n, a(n) for n = 1..996</a>
%p A068692 for n from 1 to 40 do a := prevprime((10^n-1)/9*8+2):b := convert(a,base,10):c := true:for i from 2 to nops(b) do if((b[i] mod 2)>0) then c := false:end if:end do:while(c=false) do a := prevprime(a):b := convert(a,base,10):c := true:for i from 2 to nops(b) do if((b[i] mod 2)>0) then c := false:end if:end do:end do:q[n] := a:end do:seq(q[k],k=1..40);
%t A068692 nped[n_]:=Module[{p=NextPrime[9*10^n,-1]},While[AnyTrue[Most[ IntegerDigits[ p]],OddQ],p=NextPrime[p,-1]];p]; Array[nped,20,0] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jun 14 2018 *)
%Y A068692 Cf. A068690, A068691.
%K A068692 base,nonn
%O A068692 1,1
%A A068692 _Amarnath Murthy_, Mar 03 2002
%E A068692 More terms from _Sascha Kurz_, Mar 26 2002
%E A068692 More terms from _Robert Israel_, Jul 02 2025