OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
Zak Seidov, Table of n, a(n), p, q; n=1..10000
EXAMPLE
6^2=36=(2+1)*(11+1), 16^2=256=(7+1)(31+1), 28^2=784=(7+1)(97+1).
MAPLE
filter:= proc(n) local F, f, count;
F:= select(`<`, numtheory:-divisors(n^2), n);
count:= 0;
for f in F do
if isprime(f-1) and isprime(n^2/f-1) then
count:=count+1;
if count = 2 then return false fi;
fi
od;
count=1
end proc:
select(filter, [$1..1000]); # Robert Israel, Jul 08 2016
MATHEMATICA
fQ[n_] := Block[{c = 0, p = 2}, While[p < n - 1, If[ PrimeQ[n^2/(p +1) -1], c++]; p = NextPrime@ p]; c == 1]; Select[ Range@1000, fQ] (* Robert G. Wilson v, Jul 09 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jul 08 2016
STATUS
approved