OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
601 is a term because (7^4 + 4 - 1)/4 = 601 where 7, 601 are both prime,
733 is a term because (13^3 + 3 -1)/3 = 733 where 13, 733 are both prime,
821 is a term because (3^8 + 8 - 1)/8 = 821 where 3, 821 are both prime.
MAPLE
N:= 10^6: # for terms <= N
S:= {}: p:= 1:
do
p:= nextprime(p);
if p^2/2 > N then break fi;
for k from 2 do
v:= (p^k + k - 1)/k;
if v > N then break fi;
if v::integer and isprime(v) then S:= S union {v} fi;
od od:
sort(convert(S, list)); # Robert Israel, Jun 22 2023
PROG
(PARI) isA230444(n) = {isprime(n) || return(0); my(k = 2, v, p); while (1, v = k*n+1-k; if (ispower(v, k, &p) && isprime(p), return(1)); if (v < 2^k, return(0)); k++; ); } \\ Michel Marcus, Oct 19 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Irina Gerasimova, Oct 18 2013
EXTENSIONS
More terms from Michel Marcus, Oct 19 2013
STATUS
approved