OFFSET
2,1
EXAMPLE
a(3) = 10 because 3^10 + 1 = 59050 which is divisible by 10 and ten is not a power of 3+1 or 4.
MATHEMATICA
Do[ k = n + 2; f = Transpose[ FactorInteger[ n + 1 ] ] [ [ 1 ] ]; l = Length[ f ]; While[ PowerMod[ n, k, k ] != k - 1 || Union[ Table[ IntegerQ[ Log[ f[ [ m ] ], k ] ], {m, 1, l} ] ] != {False}, k++ ]; Print[ k ], {n, 2, 47} ]
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved