A317920 Length of row n of A317721, i.e., number of elements in n-th Wieferich tuple when ordering the tuples as in A317721.

3, 5, 6, 7, 6, 7, 3, 8, 9, 9, 10, 10, 11, 9, 2, 3, 6, 9, 10, 11, 12, 13, 14, 3, 3, 4, 4, 5, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12

Offset

1,1

Links

Table of n, a(n) for n=1..75.

Example

For n = 1: Row 1 of A317721 has 3 elements, i.e., the first Wieferich tuple listed in A317721 is a "Wieferich triple", so a(1) = 3.

Prog

(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
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
printfromvec(vec) = for(k=1, #vec, if(vec[k][1]==vec[k][#vec[k]], print1(#vec[k]-1, ", ")))
forprime(p=1, , my(v=[[p]]); while(#v > 0, v=addtovec(v); printfromvec(v); v=removefromvec(v)))

Crossrefs

Cf. A297846, A317721, A317919.

Sequence in context: A181753 A082218 A111612 * A305443 A362074 A122818

Adjacent sequences: A317917 A317918 A317919 * A317921 A317922 A317923

Keyword

nonn

Author

Felix Fröhlich, Aug 21 2018

Status

approved