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 A258045 #34 Oct 28 2021 10:01:07
%S A258045 0,1,1,1,0,0,1,1,1,2,1,1,1,1,0,1,2,1,0,0,1,1,1,1,1,1,1,0,1,1,1,1,1,2,
%T A258045 2,3,1,1,1,1,1,0,1,0,0,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,0,1,0,1,1,
%U A258045 1,1,1,1,1,2,1,1,0,2,1,1,1,1,1,1,1,1,1
%N A258045 Table T(b, m) of largest exponents k such that for p = prime(m) and base b > 1 the congruence b^(p-1) == 1 (mod p^k) is satisfied, or 0 if no such k exists, read by antidiagonals (downwards).
%C A258045 a(n) > 1 if b appears in row k, column n of the table in A257833 for k > 1 and n > 1.
%F A258045 a(n, m) = T(m+1, n-m), n >=2, m = 1, 2, ..., n-1. - _Wolfdieter Lang_, Jun 29 2015
%e A258045 T(3, 5) = 2, because the largest Wieferich exponent of prime(5) = 11 in base 3 is 2.
%e A258045 Table starts
%e A258045 b=2: 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=3: 1, 0, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=4: 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=5: 2, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=6: 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=7: 1, 1, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=8: 0, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=9: 3, 0, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=10: 0, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=11: 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=12: 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=13: 2, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=14: 0, 1, 1, 0, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1 ...
%e A258045 b=15: 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=16: 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=17: 4, 2, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 b=18: 0, 0, 2, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1 ...
%e A258045 b=19: 1, 2, 1, 3, 1, 2, 1, 0, 1, 1, 1, 1, 1, 2 ...
%e A258045 b=20: 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ...
%e A258045 ....
%e A258045 The triangle a(n ,m) begins:
%e A258045 m 1 2 3 4 5 6 7 8 9 10 11 ...
%e A258045 n
%e A258045 2 0
%e A258045 3 1 1
%e A258045 4 1 0 0
%e A258045 5 1 1 1 2
%e A258045 6 1 1 1 1 0
%e A258045 7 1 2 1 0 0 1
%e A258045 8 1 1 1 1 1 1 0
%e A258045 9 1 1 1 1 1 2 2 3
%e A258045 10 1 1 1 1 1 0 1 0 0
%e A258045 11 1 1 1 1 1 1 1 1 2 1
%e A258045 12 1 1 1 1 1 1 1 1 0 1 0
%e A258045 ...
%o A258045 (PARI) for(b=2, 20, forprime(p=1, 70, k=0; while(Mod(b, p^k)^(p-1)==1, k++); if(k > 0, k--); print1(k, ", ")); print(""))
%Y A258045 Cf. A001220, A257833.
%K A258045 nonn,tabl
%O A258045 2,10
%A A258045 _Felix Fröhlich_, May 26 2015
%E A258045 Edited by _Wolfdieter Lang_, Jun 29 2015