OFFSET
1,1
COMMENTS
If p is a prime number then p divides the imaginary part of (1+2i)^A201629(p).
The numbers of this sequence may be called Fermat pseudoprimes to base 1+2i.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
Jose María Grau, A. M. Oller-Marcen, Manuel Rodriguez and D. Sadornil, Fermat test with Gaussian base and Gaussian pseudoprimes, arXiv:1401.4708 [math.NT], 2014.
MAPLE
A201629:= proc(n) if n::even then n elif n mod 4 = 1 then n-1 else n+1 fi end proc:
filter:= proc(n) not isprime(n) and type(Powmod(1+2*x, A201629(n), x^2+1, x) mod n, integer) end proc:
select(filter, [$2..1000]); # Robert Israel, Nov 06 2019
MATHEMATICA
CROSSREFS
KEYWORD
nonn
AUTHOR
José María Grau Ribas, May 19 2012
EXTENSIONS
Definition revised by José María Grau Ribas, Oct 12 2013
STATUS
approved