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A348058
a(n) = Min {k > n : A235137(k) == n (mod k)}, or -1 if no such minimum exists.
10
2, 3, 10, 5, 14, 7, 15, 16, 22, 11, 21, 13, 114, 156, 34, 17, 38, 19, 33, 25, 45, 23, 35, 80, 186, 228, 58, 29, 30, 31, 51, 64, 63, 76, 57, 37, 258, 2244, 55, 41, 86, 43, 69, 104, 94, 47, 65, 160, 1518, 372, 106, 53, 354, 81, 87, 624, 99, 59, 77, 61, 402
OFFSET
1,1
COMMENTS
Conjecture: For all n, a(n) > 0.
If a(673) > 0 then a(673) > 10^10.
LINKS
José María Grau Ribas, Table of n, a(n) for n = 1..672
MATHEMATICA
Giuga1[mu_][n_] := Giuga1[mu][n] =
Mod[Sum[PowerMod[i, EulerPhi[n], n], {i, 1, n}] - mu, n] == 0;
A348058[n_] := A348058[n] =
{Clear[ww]; Do[If[Giuga1[n][i], ww = i; Break[]], {i, n + 1, 20000000}]; ww}[1]];
Table[A348058[n], {n, 408}]
PROG
(PARI) a(n) = my(k=n+1); while (sum(i=1, k , Mod(i, k)^eulerphi(k)) != n, k++); k; \\ Michel Marcus, Sep 28 2021
CROSSREFS
Sequence in context: A230625 A048985 A337183 * A112417 A139693 A182076
KEYWORD
nonn
AUTHOR
STATUS
approved