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 A178551 #14 Aug 29 2025 08:07:09
%S A178551 223,227,229,1223,1229,2027,2029,2129,2203,2207,2213,2237,2239,2243,
%T A178551 2251,2267,2269,2273,2281,2287,2293,2297,2423,2521,2621,2729,2927,
%U A178551 3221,3229,4229,5227,6221,6229,7229,8221,9221,9227,10223,12203,12211,12239,12241,12251,12253
%N A178551 Primes with exactly two 2's.
%H A178551 Daniel Starodubtsev, <a href="/A178551/b178551.txt">Table of n, a(n) for n = 1..10000</a>
%t A178551 Select[Prime[Range[1500]],Count[IntegerDigits[#],2]==2 &] (* _Stefano Spezia_, Aug 29 2025 *)
%o A178551 (Python)
%o A178551 from sympy import isprime
%o A178551 print([i for i in range(10000) if str(i).count('2') == 2 and isprime(i)]) # _Daniel Starodubtsev_, Mar 29 2020
%Y A178551 Cf. A038618, A178550, A178552, A178553, A178554, A178555, A178556, A178557, A178558.
%K A178551 nonn,base,changed
%O A178551 1,1
%A A178551 _Lekraj Beedassy_, May 29 2010