A288491 Numbers k such that k^k*prime(k) - 1 is prime.

2, 6, 40, 56, 954

Offset

1,1

Comments

a(6) > 22000. - Giovanni Resta, Jun 12 2017

Links

Table of n, a(n) for n=1..5.

Example

a(1) = 2 because 3*2^2-1 = 11 a prime.
a(2) = 6 because 13*6^6-1 = 606527 a prime.

Mathematica

Select[Range[1000], PrimeQ[Prime[#] #^# - 1] &]

Prog

(Magma)  [n: n in [1..1000] | IsPrime(NthPrime(n)*n^n-1)];

Crossrefs

Cf. A086173.

Sequence in context: A340299 A068207 A331702 * A212883 A336959 A027161

Adjacent sequences: A288488 A288489 A288490 * A288492 A288493 A288494

Keyword

nonn,more

Author

Vincenzo Librandi, Jun 10 2017

Status

approved