OFFSET
1,1
COMMENTS
In other words, even numbers k such that k + 2 divides A014566(k) + 1.
Even terms of A213382.
4, 16, 65536 are the numbers of the form 2^(2^(2^k)), for k >= 0. Are there other members of this sequence with the form of 2^(2^(2^k))?
2^(2^(2^3)) and 2^(2^(2^4)) are terms. - Michael S. Branicky, Apr 16 2021
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..150
EXAMPLE
4 is a term because 4 + 2 = 6 divides 4^4 + 2 = 258.
MATHEMATICA
Select[Range[2, 10^4, 2], Divisible[#^# + 2, # + 2] &] (* Michael De Vlieger, Apr 03 2016 *)
PROG
(PARI) lista(nn) = forstep(n=2, nn, 2, if( Mod(n, n+2)^n == -2 , print1(n, ", "))); \\ Joerg Arndt, Apr 03 2016
(Python)
def afind(limit):
k = 2
while k < limit:
if (pow(k, k, k+2) + 2)%(k+2) == 0: print(k, end=", ")
k += 2
afind(10**7) # Michael S. Branicky, Apr 16 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Altug Alkan, Apr 03 2016
STATUS
approved