A292021 Lucas-Carmichael numbers that are congruent to 1 (mod 4).

20705, 80189, 120581, 1162349, 7274249, 8734109, 10260809, 14658349, 49412285, 90393029, 105818129, 110066669, 125532329, 256074029, 362868329, 366648281, 395032609, 434886605, 503733257, 558705449, 563601257, 574342145, 640057109, 939989609, 962529749

Offset: 1

Author

Amiram Eldar, Sep 07 2017

Keywords

• nonn

Comments

Most Lucas-Carmichael numbers are congruent to 3 (mod 4). Of the 9967 numbers less than 10^12 only 198 are congruent to 1 (mod 4).

Analogous to A185321 - Carmichael numbers that are congruent to 3 (mod 4).

Links

• Amiram Eldar, Table of n, a(n) for n = 1..198 (terms below 10^12)

Crossrefs

Intersection of A006972 and A016813.

Cf. A110885, A185321.

Programs

Mathematica

a=Select[Range[2, 10^6],!PrimeQ[#] && Union[Transpose[FactorInteger[#]][[2]]] == {1} && Union[Mod[# + 1, Transpose[FactorInteger[#]][[1]] + 1]]=={0} &] ;Select[a,Mod[#,4]==1 &] (* after Richard Pinch and Jeffrey Shallit at A006972 *)