

A271428


Values of k such that F(k)*F(k+1)1 is a prime, where F(k) is the kth Fibonacci number (A000045).


1



3, 6, 24, 42, 48, 86, 102, 138, 182, 302, 438, 506, 926, 1266, 3600, 23550, 24122, 42410, 51432, 82290
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

a(21) > 10^5.  Robert Price, Apr 14 2016


LINKS

Table of n, a(n) for n=1..20.


EXAMPLE

6 is in the sequence because F(6)*F(7)1 = 8*131 = 103, which is prime.


MATHEMATICA

Select[Range[5 * 10^3], PrimeQ[Fibonacci@ # Fibonacci[# + 1]  1] &] (* Michael De Vlieger, Apr 07 2016 *)


PROG

(PARI) L=List(); for(k=1, 1000, if(ispseudoprime(fibonacci(k)*fibonacci(k+1)1), listput(L, k))); Vec(L)


CROSSREFS

Cf. A000045, A271427.
Sequence in context: A106213 A129520 A047167 * A148649 A148650 A148651
Adjacent sequences: A271425 A271426 A271427 * A271429 A271430 A271431


KEYWORD

nonn,more


AUTHOR

Colin Barker, Apr 07 2016


EXTENSIONS

a(15) from Michael De Vlieger, Apr 07 2016
a(16)a(20) from Robert Price, Apr 14 2016


STATUS

approved



