A098651 Where A098650 reaches a record.

1, 2, 6, 15, 30, 39, 78, 105, 910, 7735, 18655, 98605, 214415, 265031, 283309, 313937, 373395, 432419, 440115, 441285, 497211, 573287, 658502, 1035741, 1198806

Offset: 1

Author

Robert G. Wilson v, Sep 18 2004

Keywords

• nonn
• more

Crossrefs

Cf. A098650, A098652.

Programs

Mathematica

PrimeFactors[n_] := Flatten[ Table[ # [[1]], {1} ] & /@ FactorInteger[ n ]]; f[n_] := Block[{k = n + 1}, If[EvenQ[k], k++ ]; While[ PrimeQ[k] || Union[ PowerMod[ PrimeFactors[n], k - 1, k]] != {1}, k += 2]; k]; a = {1}; b = {9}; Do[ If[ SquareFreeQ[n], c = f[n]; If[c > b[[ -1]], AppendTo[a, n]; AppendTo[b, c]; Print[n]]], {n, 2, 145000}]; a

Extensions

a(13)-a(25) from Amiram Eldar, Jul 07 2021