OFFSET

1,1

COMMENTS

These Fibonacci numbers F(n) have no prime factor congruent to 2 mod 3 to an odd power.

Note that F(12) = 144 = 2^4 * 3^2. - T. D. Noe, Aug 27 2012

LINKS

MATHEMATICA

Select[Range[2, 200, 2], Length[FindInstance[x^2 + 3*y^2 == Fibonacci[#], {x, y}, Integers]] > 0 &] (* T. D. Noe, Aug 27 2012 *)

PROG

(PARI) for(i=2, 500, a=factorint(fibonacci(i))~; has=0; for(j=1, #a, if(a[1, j]%3==2&&a[2, j]%2==1, has=1; break)); if(has==0&&i%2==0, print(i", ")))

CROSSREFS

KEYWORD

nonn

AUTHOR

V. Raman, Aug 23 2012

EXTENSIONS

Edited by N. J. A. Sloane, Aug 23 2012

12 added by T. D. Noe, Aug 27 2012

Added 4 more terms - V. Raman, Aug 28 2012

STATUS

approved