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

1,1

Comments

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

p*a(n) is a term for all primes p with A020639(a(n))<p < A006530(a(n));

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

Links

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

Example

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

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 *)

Crossrefs

Cf. A085231.

Sequence in context: A068993 A138592 A357850 * A085234 A057714 A143907

Adjacent sequences: A085229 A085230 A085231 * A085233 A085234 A085235

Keyword

nonn

Author

Reinhard Zumkeller, Jun 22 2003

Status

approved