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 A249162 #24 Nov 02 2021 22:24:31
%S A249162 2,5,3,7,17,5,19,131,7,7,127,659,19,19,11,911,503,127,127,3,13,7331,
%T A249162 9833,911,911,17,19,17,167149,49603,7331,7331,131,127,131,19,387749,
%U A249162 327317,167149,167149,659,911,659,127,23,17153317,13900147,387749,387749,503
%N A249162 Square array A(p, b) read by antidiagonals in which rows are indexed by successive prime numbers p_i and row b(p_i) gives the smallest prime base b_n to which q = (p_i, b_(n-1)) is a Wieferich prime.
%e A249162 A(6,4) = 911, since the 6th prime is 13 and the smallest prime Wieferich base for 13 is 19. Applying this procedure recursively to the resulting bases a total of b-1 = 3 times leads to 911.
%e A249162 Array starts:
%e A249162 2 5 7 19 127 911 7331 167149 387749 17153317 ...
%e A249162 3 17 131 659 503 9833 49603 327317 13900147 144229223 ...
%e A249162 5 7 19 127 911 7331 167149 387749 17153317 ...
%e A249162 7 19 127 911 7331 167149 387749 17153317 432383657 ...
%e A249162 11 3 17 131 659 503 9833 49603 327317 ...
%e A249162 13 19 127 911 7331 167149 387749 ...
%e A249162 17 131 659 503 9833 49603 327317 ...
%e A249162 19 127 911 7331 167149 387749 17153317 ...
%e A249162 23 263 79 31 229 503 ...
%e A249162 29 41 313 1499 941 12011 ...
%e A249162 ...
%o A249162 (PARI) forprime(p=1, 30, b=1; i=0; q=p; print1(p, ", "); while(i < 6, b++; if(Mod(b, q^2)^(q-1)==1 && isprime(b), print1(b, ", "); q=b; b=1; i++)); print(""))
%Y A249162 Cf. A001220, A244249.
%Y A249162 Second column of table is A125636.
%K A249162 nonn,tabl
%O A249162 1,1
%A A249162 _Felix Fröhlich_, Oct 22 2014