OFFSET
1,1
REFERENCES
Joe Roberts, Lure of the Integers, "Integer 4181". (There is a misprint in the definition.)
LINKS
Robert Israel, Table of n, a(n) for n = 1..670
EXAMPLE
4181 is the 19th Fibonacci number, it is composite and it is congruent to (19/5) mod 19, so 4181 is a term.
MAPLE
a:= 1: b:= 1: R:= NULL: count:= 0:
for n from 3 while count < 50 do
t:= a; a:= b; b:= t+b;
if b - NumberTheory:-LegendreSymbol(n, 5) mod n = 0 and not isprime(b) then
R:= R, b; count:= count+1;
fi
od:
R; # Robert Israel, Jul 19 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected by Robert Israel, Jul 19 2023
STATUS
approved