OFFSET
1,1
COMMENTS
Empirically, numbers in this sequence seem to have few divisors.
This sequence appears to be the union of A130763 and the squares of A225649. - Kellen Myers, Apr 21 2015
MATHEMATICA
seq[n_] := Select[Range[n], PrimeQ[DivisorSigma[0, #] - 2] &] (* Kellen Myers, Apr 21 2015 *)
PROG
(Magma) [n: n in [1..200] | IsPrime(NumberOfDivisors(n)-2)]; // Vincenzo Librandi, Apr 21 2015
(PARI) isok(m) = isprime(numdiv(m)-1); \\ Michel Marcus, Jan 13 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Rory Glover, Feb 22 2015
EXTENSIONS
Terms fixed by Kellen Myers, Apr 21 2015
Name corrected by Michel Marcus, Jan 13 2023
STATUS
approved