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 A105436 #14 Jul 02 2025 16:02:02
%S A105436 2,3,2,2,13,3,29,7,17,17,3,3,2,3,197,5,13,173,2,13,53,73,199,2,23,73,
%T A105436 599,239,547,59,409,1009,1277,19,3,383,137,13,653,103,139,227,19,127,
%U A105436 359,193,1123,3,97,1447,839,109,3,47,17,7,269,2,1657,1973,709,5233,809
%N A105436 Smallest prime that remains prime when a string of n 1's is appended to it.
%e A105436 a(2)=2 because it is the first prime followed by 3,41,101,107,113,137,... all remaining primes when 11 is appended to each of them.
%p A105436 with(numtheory); for n from 1 to 100 do for i from 1 to 5000 do if isprime(ithprime(i)*10^n + sum(10^j, j=0..n-1)) then printf(`%d,`, ithprime(i)); break; fi: od:od: # _James Sellers_, Apr 09 2005
%t A105436 f[n_] := Block[{k = 1, t = Table[1, {n}]}, While[id = IntegerDigits[ Prime[k]]; id[[ -1]] == 1 || !PrimeQ[ FromDigits[ Join[id, t]]], k++ ]; Prime[k]]; Table[ f[n], {n, 0, 62}] (* _Robert G. Wilson v_, Apr 09 2005 *)
%Y A105436 Cf. A065821, A105437.
%K A105436 nonn,base
%O A105436 0,1
%A A105436 _Lekraj Beedassy_, Apr 08 2005
%E A105436 More terms from _Robert G. Wilson v_ and _James Sellers_, Apr 09 2005