A206713
Number of solutions (n,k) of s(k)=s(n) (mod n), where 1<=kA000045(k+1) (Fibonacci numbers).
0, 0, 1, 1, 1, 0, 1, 1, 0, 3, 2, 1, 1, 0, 1, 1, 1, 3, 0, 1, 3, 0, 2, 1, 1, 1, 2, 6, 0, 3, 5, 0, 2, 0, 4, 1, 4, 1, 2, 4, 3, 0, 1, 2, 2, 2, 5, 2, 0, 1, 2, 1, 1, 2, 2, 0, 5, 3, 2, 4, 4, 2, 2, 1, 4, 0, 3, 1, 1, 3, 8, 1, 1, 0, 8, 1, 2, 3, 2, 3, 3, 0, 6, 1, 1, 3, 6, 8, 1, 0, 3, 3, 6, 0, 5, 1, 0, 1, 1
Offset: 2
Keywords
Examples
s(11)=144 = A000045(12); the numbers s(j) for j<11 are 143,142,141,139,136,131,110,89,55, of which three are multiples of 3, so that a(11)=3.
Programs
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Mathematica
s[k_] := Fibonacci[k + 1]; f[n_, k_] := If[Mod[s[n] - s[k], n] == 0, 1, 0]; t[n_] := Flatten[Table[f[n, k], {k, 1, n - 1}]] a[n_] := Count[Flatten[t[n]], 1] Table[a[n], {n, 2, 120}] (* A206713 *)