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 A298729 #36 Apr 16 2018 12:36:21
%S A298729 137777777,177777773,177777779,197777777,307777777,347777777,
%T A298729 437777777,527777777,547777777,577777777,587777777,647777777,
%U A298729 697777777,777777701,777777739,777777743,777777751,777777799,787777777,827777777,947777777,967777777,1247777777,1277777771,1277777773,1457777777,1487777777
%N A298729 Prime numbers whose decimal expansion includes a substring of seven consecutive 7's.
%t A298729 s = {7, 7, 7, 7, 7, 7, 7}; lst = {}; k = 1; While[k < 10001, l = 1; il = 12;
%t A298729 While[l < il, p = FromDigits@ Flatten@ Insert[ IntegerDigits[k, 10, 10], s, l];
%t A298729 If[PrimeQ@ p, AppendTo[lst, p]]; l++]; k++]; Union@ lst (* _Robert G. Wilson v_, Feb 08 2018 *)
%o A298729 (PARI) is(n) = my(v=vector(7, x, 7), d=digits(n)); for(k=1, #d-6, if([d[k], d[k+1], d[k+2], d[k+3], d[k+4], d[k+5], d[k+6]]==v, return(1))); 0
%o A298729 forprime(p=1, , if(is(p), print1(p, ", "))) \\ _Felix Fröhlich_, Mar 06 2018
%Y A298729 Cf. A102764, A167282, A108844, A083978.
%K A298729 base,nonn,less
%O A298729 1,1
%A A298729 _Yohei Furutono_, Jan 25 2018