OFFSET
1,1
EXAMPLE
T(4, 3) = 197, because 197 is the smallest base b such that p = prime(4) = 7 is the 3rd base-b Wieferich prime.
Triangle T(n, k) starts:
5;
8, 17;
7, 26, 449;
30, 18, 197, 557;
3, 9, 118, 1207, 19601;
22, 146, 19, 361, 8201, 132857;
38, 40, 224, 249, 4625, 296449, 4486949;
54, 28, 68, 99, 4033, 4625, 296449, 126664001;
42, 130, 28, 118, 557, 8201, 997757, 24800401, 2363321449;
PROG
(PARI) nextwiefbase(n, a) = a++; while(Mod(a, n^2)^(n-1)!=1, a++); a
wiefrank(n, a) = i=0; forprime(p=1, n, if(Mod(a, p^2)^(p-1)==1, i++)); i
trianglerows(n) = i=1; while(i <= n, p=prime(i); for(k=1, i, b=2; while(wiefrank(p, b)!=k, b=nextwiefbase(p, b)); print1(b, ", ")); print(""); i++)
trianglerows(9) \\ print first nine rows of the triangle
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Felix Fröhlich, Jun 10 2015
EXTENSIONS
More terms from Max Alekseyev, Oct 14 2023
STATUS
approved