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 A178554 #17 Jul 16 2022 07:10:16 %S A178554 555557,1555553,2555551,3555551,3555557,4555559,5055551,5055559, %T A178554 5355551,5505551,5535559,5550553,5550557,5554553,5555057,5555059, %U A178554 5555357,5555507,5555509,5555527,5555567,5555591,5555653,5556557,5556559,5557553 %N A178554 Primes with exactly five 5's. %H A178554 Daniel Starodubtsev, <a href="/A178554/b178554.txt">Table of n, a(n) for n = 1..10000</a> %t A178554 Select[Prime[Range[PrimePi[55555],1000000]],Count[IntegerDigits[#],5]==5&] (* _Harvey P. Dale_, Dec 20 2010 *) %o A178554 (PARI) isok(p) = isprime(p) && (#select(x->(x==5), digits(p)) == 5); \\ _Michel Marcus_, Mar 15 2020 %Y A178554 Cf. A038618, A178550, A178551, A178552, A178553, A178555, A178556, A178557, A178558. %K A178554 nonn,base %O A178554 1,1 %A A178554 _Lekraj Beedassy_, May 29 2010 %E A178554 Missing a(14) = 5554553 inserted by _Daniel Starodubtsev_, Mar 15 2020