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 A199977 #13 Mar 01 2021 02:01:13
%S A199977 59,101,103,107,109,239,251,257,269,293,307,349,353,401,409,439,457,
%T A199977 479,503,509,521,523,541,547,563,569,577,587,599,601,607,619,653,659,
%U A199977 691,701,709,757,787,809,853,857,859,877,907,947,997,1009,1013,1019,1021
%N A199977 Primes whose multiplicative digital root is 0.
%C A199977 Complement of A199978 with respect to A034048.
%H A199977 Robert Israel, <a href="/A199977/b199977.txt">Table of n, a(n) for n = 1..10000</a>
%e A199977 Prime 239 is in sequence because 2*3*9 = 45, 4*5 = 20, 2*0 = 0.
%p A199977 mdr:= proc(n) local L,r;
%p A199977 r:= n;
%p A199977 while r >= 10 do
%p A199977 r:= convert(convert(r,base,10),`*`)
%p A199977 od;
%p A199977 r
%p A199977 end proc:
%p A199977 select(mdr=0, [seq(ithprime(i),i=1..1000)]); # _Robert Israel_, Feb 28 2021
%t A199977 digRoot[n_] := Module[{k = n}, While[k > 9, k = Times @@ IntegerDigits[k]]; k]; Select[Range[1200], PrimeQ[#] && digRoot[#] == 0 &] (* _T. D. Noe_, Nov 23 2011 *)
%Y A199977 Cf. A199978 (nonprime numbers whose multiplicative digital root is 0).
%K A199977 nonn,base
%O A199977 1,1
%A A199977 _Jaroslav Krizek_, Nov 13 2011