OFFSET
1,1
COMMENTS
a(11) > 1000. - Donovan Johnson, Jun 06 2009
a(11) >= 1801. Inclusion of 1801 depends on the factorization of Fibonacci(1801), a 377-digit composite number. - Tyler Busby, Jan 14 2023
LINKS
EXAMPLE
F(19) = 4181 = 37 * 113, reverse(F(19)) = 1814 = 2 * 907.
MAPLE
with(combinat): with(numtheory): rev:=proc(n) local nn: nn:=convert(n, base, 10): add(nn[nops(nn)+1-j]*10^(j-1), j=1..nops(nn)) end: a:=proc(n): if rev(fibonacci(n))<>fibonacci(n) and bigomega(fibonacci(n))=2 and bigomega(rev(fibonacci(n)))=2 then n else fi end: seq(a(n), n=1..200); # Emeric Deutsch, Jul 26 2006
MATHEMATICA
fspQ[n_]:=Module[{f=Fibonacci[n]}, f!=IntegerReverse[f]&&PrimeOmega[f] == PrimeOmega[IntegerReverse[f]]==2]; Select[Range[470], fspQ] (* Harvey P. Dale, Jul 24 2016 *)
PROG
(PARI) is(k) = {(fib=fibonacci(k))!=(fibrev=fromdigits(Vecrev(digits(fib)))) && (bigomega(fib)==2 && bigomega(fibrev)==2)} \\ Tyler Busby, Jan 07 2023
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Jonathan Vos Post and G. L. Honaker, Jr., Nov 13 2004
EXTENSIONS
More terms from Emeric Deutsch, Jul 26 2006
a(10) from Donovan Johnson, Jun 06 2009
STATUS
approved