OFFSET
1,1
COMMENTS
Or numbers k such that A338762(k) = 0.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
EXAMPLE
39 is in the sequence because F(39)^2 + 1 = 63245986^2 + 1 = 73*149*2221*2789*59369 with no Fibonacci prime factors.
38 is not in the sequence because F(38)^2 + 1 = 39088169^2 + 1 = 2*73*149*233*2221*135721. The numbers and 2, 233 are Fibonacci prime factors.
MAPLE
a:= proc(n) local F, m, t; F, m, t:=
[1, 2], 0, (<<0|1>, <1|1>>^n)[2, 1]^2+1;
while F[2]<=t do if isprime(F[2]) and irem(t, F[2])=0
then m:=F[2] fi; F:= [F[2], F[1]+F[2]]
od; m
end:
for n from 1 to 100 do :
if a(n)=0 then printf(`%d, `, n):else fi:
od: # program from Alois P. Heinz, adapted for the sequence. See A338762.
PROG
(PARI) isok(n) = {my(i=0, f=0, x=fibonacci(n)^2+1, m=0); while(f < x, i++; f = fibonacci(i); if (ispseudoprime(f) && (x%f) == 0, return (0)); ); return(1); } \\ Michel Marcus, Nov 13 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Nov 09 2020
STATUS
approved