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Number of Wieferich tuples with A297846(n) as largest member, i.e., number of rows of the array in A317721 where A297846(n) is the largest element of that row.
3

%I #12 Sep 07 2018 04:07:06

%S 1,3,2,7,1,2,1,6,1,317,1,1,230,580

%N Number of Wieferich tuples with A297846(n) as largest member, i.e., number of rows of the array in A317721 where A297846(n) is the largest element of that row.

%e For n = 2: The second prime that occurs in column 1 of the array in A317721 is 359. 359 occurs as the largest element in 3 rows of the array, so a(2) = 3.

%o (PARI) addtovec(vec) = my(w=[], vmax=0); for(t=1, #vec, if(vecmax(vec[t]) > vmax, vmax=vecmax(vec[t]))); for(k=1, #vec, forprime(q=1, vmax, if(Mod(vec[k][#vec[k]], q^2)^(q-1)==1, w=concat(w, [0]); w[#w]=concat(vec[k], [q])))); w

%o removefromvec(vec) = my(w=[]); for(k=1, #vec, if(vecsort(vec[k])==vecsort(vec[k], , 8), w=concat(w, [0]); w[#w]=vec[k])); w

%o forprime(p=1, , my(v=[[p]], i=0); while(#v > 0, v=addtovec(v); for(k=1, #v, if(v[k][1]==v[k][#v[k]], i++)); v=removefromvec(v)); if(i > 0, print1(i, ", ")))

%Y Cf. A297846, A317721, A317920.

%K nonn,more

%O 1,2

%A _Felix Fröhlich_, Aug 21 2018