

A127837


Numbers n such that ((n+1)^n1)/n^2 is a prime.


3




OFFSET

1,1


COMMENTS

All terms are primes. Corresponding primes of the form ((n+1)^n1)/n^2 are listed in A128466(n) = {2, 7, 311, 7563707819165039903, ...}.
It seems that if p is in the sequence then the first three numbers n such that n^2 divides (p+1)^n1 are: 1, p & ((p+1)^p1)/p. 2 is in the sequence and the first three terms of A127103 are : 1, 2 & ((2+1)^21)/2; 3 is in the sequence and the first three terms of A127104 are : 1, 3 & ((3+1)^31)/3; 5 is in the sequence and the first three terms of A127106 are : 1, 5 & ((5+1)^51)/5.
No other terms below 20000.  Max Alekseyev, Apr 25 2007


LINKS

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


EXAMPLE

4357 is in the sequence because (4358^43571)/4357^2 is prime.


CROSSREFS

Cf. A128466, A037205, A060072, A060073, A058128, A128456, A127103, A127104, A127106, A128398.
Sequence in context: A092506 A275159 A127063 * A253646 A004249 A268210
Adjacent sequences: A127834 A127835 A127836 * A127838 A127839 A127840


KEYWORD

hard,more,nonn


AUTHOR

Farideh Firoozbakht and Alexander Adamchuk, Mar 13 2007


STATUS

approved



