A217611 - OEIS

A217611

Primes p such that the octal expansion of 1/p has a unique period length.

3, 7, 19, 73, 87211, 262657, 18837001, 77158673929, 5302306226370307681801, 19177458387940268116349766612211, 6113142872404227834840443898241613032969, 328017025014102923449988663752960080886511412965881

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OFFSET

1,1

COMMENTS

Also called generalized unique primes in base 8.

LINKS

Arkadiusz Wesolowski, Table of n, a(n) for n = 1..27

C. K. Caldwell, "Top Twenty" page, Generalized Unique

Wikipedia, Octal

MATHEMATICA

lst = {}; Do[c = Cyclotomic[n, 8]; q = c/GCD[n, c]; If[PrimePowerQ[q], p = FactorInteger[q][[1, 1]]; AppendTo[lst, p]], {n, 138}]; Sort[lst]

CROSSREFS

Cf. A019326, A040017 (unique-period primes in base 10).

Sequence in context: A135741 A328159 A163571 * A322852 A243583 A215487

Adjacent sequences: A217608 A217609 A217610 * A217612 A217613 A217614

KEYWORD

base,nonn

AUTHOR

Arkadiusz Wesolowski, Oct 08 2012

STATUS

approved