Voozh

A367231

Carmichael numbers k such that the multiplicative order of 2 modulo k is odd.

15841, 52633, 5049001, 68154001, 104852881, 238244041, 382536001, 3215031751, 3863326897, 7211236033, 8214723001, 15462960481, 22008493921, 23000028481, 29392867201, 31708772257, 41217865921, 53125756201, 60518537641, 74190097801, 77874636001, 83828294551, 103387371361

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

These Carmichael numbers seem to be relatively rare: among the 4279356 Carmichael numbers below 2^64 only 3097 are terms of this sequence.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000 (calculated using data from Claude Goutier)

Claude Goutier, Compressed text file carm10e22.gz containing all the Carmichael numbers up to 10^22.

Index entries for sequences related to Carmichael numbers.

MATHEMATICA

Select[2*Range[3*10^6] + 1, Mod[#, CarmichaelLambda[#]] == 1 && CompositeQ[#] && OddQ[MultiplicativeOrder[2, #]] &]

PROG