A153519 Nonprime numbers k such that 10^k == 10 (mod k) and are not Carmichael numbers.

1, 6, 9, 10, 15, 18, 30, 33, 45, 55, 90, 91, 99, 165, 246, 259, 370, 385, 451, 481, 495, 505, 657, 703, 715, 909, 1035, 1045, 1233, 1626, 2035, 2409, 2981, 3333, 3367, 3585, 4005, 4141, 4187, 4521, 4545, 5005, 5461, 6533, 6541, 6565, 7107, 7471, 7777, 8149

Offset

1,2

Comments

Old name: Members of A121014 which are not Carmichael numbers A002997.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[8000], !PrimeQ[#] && PowerMod[10, #, #] == Mod[10, #] && !(# > 1 && Divisible[# - 1, CarmichaelLambda[#]]) &] (* Amiram Eldar, Mar 19 2020 *)

Prog

(PARI) isok(n) = !isprime(n) && !is_A002997(n) && (Mod(10^n, n) == Mod(10, n)); \\ Michel Marcus, Nov 06 2013

Crossrefs

Cf. A002997, A122780, A153508, A153513, A153514, A153515.

Sequence in context: A359277 A054020 A121014 * A020219 A175634 A134622

Adjacent sequences: A153516 A153517 A153518 * A153520 A153521 A153522

Keyword

nonn

Author

Artur Jasinski, Dec 28 2008

Extensions

New name from Michel Marcus, Nov 06 2013

Status

approved