A218766 Composite numbers with both 10 and -10 as primitive root.

289, 841, 3721, 4913, 9409, 11881, 12769, 22201, 24389, 32761, 37249, 52441, 54289, 66049, 72361, 83521, 97969, 113569, 151321, 187489, 212521, 226981, 259081, 292681, 332929, 351649, 491401, 502681, 674041, 707281, 734449, 877969, 885481, 908209, 912673

Offset

1,1

Comments

The powers of primes from A007349.

Intersection of A002808, A167797 and A167806.

Links

Arkadiusz Wesolowski, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Primitive Root

Example

12769 = 113^2 belongs to this sequence because 113 is in A007349.

Mathematica

lst = {}; r = 912673; Do[If[PrimeQ[i] && MultiplicativeOrder[10, i] == MultiplicativeOrder[-10, i] == i - 1, n = 2; While[(p = i^n) <= r, AppendTo[lst, p]; n++]], {i, Floor@Sqrt[r]}]; Sort[lst]

Crossrefs

Cf. A007349.

Sequence in context: A156572 A157990 A261111 * A188186 A112077 A152934

Adjacent sequences: A218763 A218764 A218765 * A218767 A218768 A218769

Keyword

nonn

Author

Arkadiusz Wesolowski, Nov 05 2012

Status

approved