A057908 Numbers n such that 4^n - n is prime.

1, 3, 5, 35, 95, 1323, 24747

Offset

1,2

Comments

a(8) > 2*10^5. - Robert Price, Feb 11 2014

Links

Table of n, a(n) for n=1..7.

Mathematica

Do[ If[ PrimeQ[ 4^n - n ], Print[ n ] ], {n, 0, 3000} ]

Prog

(PARI) for(k=1, 10^6, if(ispseudoprime(4^k-k), print1(k, ", "))); /* Joerg Arndt, Apr 07 2013 */

Crossrefs

Sequence in context: A055786 A001790 A173092 * A120828 A077784 A325582

Adjacent sequences: A057905 A057906 A057907 * A057909 A057910 A057911

Keyword

nonn,more

Author

Robert G. Wilson v, Nov 16 2000

Extensions

a(7) from Robert Price, Feb 11 2014

Status

approved