OFFSET
1,1
COMMENTS
EXAMPLE
30 = 2*3*5 and sigma(30) = 72 = 2^3*3^2 hence 30 is in the sequence.
MAPLE
select(t -> min(numtheory:-factorset(t))=min(numtheory:-factorset(numtheory:-sigma(t))), [$2..1000]); # Robert Israel, Nov 14 2017
MATHEMATICA
Rest@ Select[Range@ 150, SameQ @@ Map[FactorInteger[#][[1, 1]] &, {#, DivisorSigma[1, #]}] &] (* Michael De Vlieger, Nov 13 2017 *)
PROG
(Magma) [n: n in [2..1000000] | Minimum(PrimeDivisors(SumOfDivisors(n))) eq Minimum(PrimeDivisors(n))]
(PARI) isok(n) = factor(n)[1, 1] == factor(sigma(n))[1, 1]; \\ Michel Marcus, Nov 14 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Nov 13 2017
EXTENSIONS
Added n>1 to definition - N. J. A. Sloane, Feb 03 2018
STATUS
approved