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 A102611 #12 Apr 03 2023 10:36:10
%S A102611 2,5,6,8,9,12,17,18,23,24,26,27,36,38,41,48,50,54,62,65,69,71,74,75,
%T A102611 78,83,86,92,93,96,101,104,111,116,117,122,123,125,131,134,135,138,
%U A102611 141,150,152,153,158,164,170,173,174,179,180,194,195,197,201,204,212,213,215
%N A102611 Numbers n such that the number n77 is prime.
%H A102611 Harvey P. Dale, <a href="/A102611/b102611.txt">Table of n, a(n) for n = 1..1000</a>
%H A102611 Chris Caldwell, <a href="https://t5k.org/lists/small/1000.txt">The first 1,000 primes</a>.
%e A102611 At n=2, n77 = 277 (prime).
%e A102611 At n=27, n77 = 2777 (prime).
%e A102611 At n=78, n77 = 7877 (prime).
%t A102611 fQ[n_] := PrimeQ[ FromDigits[ Join[ IntegerDigits[n], {7, 7}]]]; Select[ Range[218], fQ[ # ] &] (* _Robert G. Wilson v_, Feb 04 2005 *)
%t A102611 Select[Range[300],PrimeQ[100#+77]&] (* _Harvey P. Dale_, Mar 17 2015 *)
%o A102611 (PARI) is(n)=isprime(100*n+77) \\ _Charles R Greathouse IV_, Jun 06 2017
%K A102611 nonn,base
%O A102611 1,1
%A A102611 _Parthasarathy Nambi_, Jan 30 2005
%E A102611 More terms from _Robert G. Wilson v_, Feb 04 2005