A085232 In canonical prime factorization: power of smallest prime factor is less than power of greatest prime factor.

6, 10, 14, 15, 18, 20, 21, 22, 26, 28, 30, 33, 34, 35, 36, 38, 39, 42, 44, 46, 50, 51, 52, 54, 55, 57, 58, 60, 62, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 98, 99, 100, 102, 104, 105, 106, 108, 110, 111, 114, 115

Offset: 1

Author

Reinhard Zumkeller, Jun 22 2003

Keywords

• nonn

Comments

A028233(a(n)) < A053585(a(n));

p*a(n) is a term for all primes p with A020639(a(n))

A006530(a(n));

a(n)=A057714(n-1) for n<28: a(28)=60, A057714(28-1)=62.

Examples

			60 = 2^2 * 3 * 5 with 2^2=4 < 5, therefore 60 is a term.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..2500

Crossrefs

Cf. A085231.

Programs

Mathematica

spfQ[n_]:=Module[{fi=FactorInteger[n]},Length[fi]>1&&fi[[1,1]]^fi[[1,2]] < fi[[-1,1]]^fi[[-1,2]]]; Select[Range[120],spfQ] (* Harvey P. Dale, Jul 30 2018 *)