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 A069691 #15 Aug 27 2025 18:07:52 %S A069691 101,113,127,131,149,151,163,173,181,191,1103,1117,1123,2131,2141, %T A069691 1151,1163,1171,1181,1193,1201,1213,1223,1231,1249,1259,2267,1277, %U A069691 1283,1291,1301,1319,1321,2333,2341,2351,1361,1373,1381,1399,1409,2411,1423,1433,1447 %N A069691 Smallest prime with internal digits = n; or 0 if no such number exists. %C A069691 By placing one digit on both sides of n one get 36 different numbers that might be primes ( 1 to 9 on left and 1,3,7,9 on right). If none of these numbers is a prime then a(n) = 0. %C A069691 The smallest value of n for which a(n) = 0 is 2437 = A032734(0). - _Rick L. Shepherd_ and _Reinhard Zumkeller_, Jul 17 2002 %H A069691 Robert Price, <a href="/A069691/b069691.txt">Table of n, a(n) for n = 0..10000</a> %H A069691 <a href="/index/Pri#piden">Index entries for primes involving decimal expansion of n</a> %e A069691 a(25) = 1259 is prime with internal digits =25. %Y A069691 Cf. A032734, A030665, A069691, A077501, A084413. %K A069691 nonn,base,changed %O A069691 0,1 %A A069691 _Amarnath Murthy_, Apr 06 2002 %E A069691 Corrected and extended by Larry Reeves, _Rick L. Shepherd_ and _Reinhard Zumkeller_, Jul 17 2002