A110885 Lucas-Carmichael numbers that are not congruent to 11 (mod 12).

399, 5719, 20705, 80189, 120581, 162687, 482143, 663679, 1162349, 7274249, 8734109, 9486399, 10260809, 10397407, 14658349, 14970499, 25603599, 29010079, 32869759, 49412285, 77801359, 90393029, 95972799, 99467679, 105818129, 110066669, 125532329, 126325399

Offset: 1

Author

Walter Kehowski, Sep 19 2005

Keywords

• nonn

Comments

There are 9967 Lucas-Carmichael numbers less than 10^12, and all but 332 are congruent to 11 (mod 12).

Examples

			5719=7*19*43=7 mod 12.
		

Links

• Robert G. Wilson v, Table of n, a(n) for n = 1..333

Crossrefs

Cf. A006972.

Programs

Maple

with(numtheory); LC:=[]: for z from 1 to 1 do for m from 1 to 2000000 do n:=2*m+1; if not(isprime(n)) and issqrfree(n) then PF:=factorset(n); lcb:=true; for x in PF do if (n+1) mod (x+1) > 0 then lcb:=false fi od; if lcb then LC:=[op(LC),n]; fi; fi; #not od; #m od; #z select(proc(z) not(z mod 12 = 11) end, LC);

Extensions

a(10) onward from Robert G. Wilson v, Feb 12 2015