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 A113889 #6 Mar 24 2021 05:58:43
%S A113889 0,73,0,0,77711,77713,7717,719,7723,77777777777777777729,77731,777737,
%T A113889 7741,743,77747,7753,7759,761,77777777767,7777777777771,773,
%U A113889 777777777777777777777777777777777777777777777777777777777777777779
%N A113889 Smallest prime of the form: all sevens followed by prime(n); a(n) > prime(n); or 0 if no such prime exists.
%C A113889 Prime(n) is all zeros followed by prime(n).This is all sevens followed by prime(n). Conjecture: a(n) is nonzero if n >4.
%C A113889 The conjecture has been verified for n<100. - Joshua Albert (jba138(AT)psu.edu), Jan 20 2006
%e A113889 a(9) = 7723, as 723 is composite, prime(9) = 23.
%t A113889 Join[{0,73,0,0},Flatten[Select[#,PrimeQ,1]&/@Table[FromDigits[ PadLeft[ IntegerDigits[n],i,7]],{n,Prime[Range[5,30]]},{i,IntegerLength[ n]+1, 100}]]] (* _Harvey P. Dale_, Nov 20 2013 *)
%Y A113889 Cf. A113884, A114785, A113886, A113887, A085074.
%K A113889 base,nonn
%O A113889 1,2
%A A113889 _Amarnath Murthy_, Nov 18 2005
%E A113889 More terms from Joshua Albert (jba138(AT)psu.edu), Jan 20 2006