A335721 Integers m such that A014448(m) == 5 (mod m).

1, 213, 85887, 974943, 2463831, 3952791, 217643749, 286354743, 874273639, 14029228621

Offset: 1

Author

Chai Wah Wu, Jun 18 2020

Keywords

• nonn
• more

Comments

Inspired by A335670.

All terms greater than 1 are odd and composite. - Michel Marcus, Jun 19 2020

Crossrefs

Cf. A014448, A335670, A335722.

Programs

Mathematica

Select[Range[10^5], Divisible[LucasL[3#] - 5, #] &] (* Amiram Eldar, Jun 19 2020 *)

PARI

f(n) = my(w=quadgen(5)); (1+2*w)^n + (3-2*w)^n; \\ A014448
isok(m) = (m%2) && (m>1) && !isprime(m) && ((f(m) % m) == 5); \\ Michel Marcus, Jun 19 2020

Extensions

a(7)-a(10) from Giovanni Resta, Jun 19 2020