A344827 - OEIS

%I #5 May 31 2021 21:31:22

%S 449,226,1207,606,3469,653,5649,26645,7805,6154,36088,14368,49662,

%T 66565,153463,40667,760637,31871,265418,411467,484205,148989,688285,

%U 796095,1920186,747071,3516680,569812,905979,3193580,3303343,1967646,1728157,4436267,912246

%N a(n) is the smallest b > 1 such that prime(n), prime(n+1) and prime(n+2) are all base-b Wieferich primes.

%o (PARI) a(n) = my(v=[prime(n)]); while(#v < 3, v=concat(v, nextprime(v[#v]+1))); for(b=2, oo, for(k=1, #v, if(Mod(b, v[k]^2)^(v[k]-1)!=1, break, if(k==#v, return(b)))))

%Y Cf. A039678, A259075. Column 3 of A286816.

%Y Cf. smallest b > 1 such that prime(n+i) is a base-b Wieferich prime for each i = 0..k: A039678 (k=0), A259075 (k=1), A344828 (k=3), A344829 (k=4), A344830 (k=5), A344831 (k=6), A344832 (k=7).

%K nonn

%O 1,1

%A _Felix Fröhlich_, May 29 2021