cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A072412 Numbers k such that the LCM of exponents in the prime factorization of k does not equal the largest exponent.

Original entry on oeis.org

72, 108, 200, 288, 360, 392, 432, 500, 504, 540, 600, 648, 675, 756, 792, 800, 864, 936, 968, 972, 1125, 1152, 1176, 1188, 1224, 1323, 1350, 1352, 1368, 1372, 1400, 1404, 1440, 1500, 1568, 1656, 1800, 1836, 1944, 1960, 2000, 2016, 2052, 2088, 2160
Offset: 1

Views

Author

Labos Elemer, Jun 17 2002

Keywords

Comments

This sequence differs from the Achilles numbers (A052486).

Examples

			k = 360 = 2*2*2*3*3*5, exponent set = {3,2,1}; LCM=6, max=3.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[2000], LCM @@ (e = FactorInteger[#][[;; , 2]]) != Max[e] &] (* Amiram Eldar, Jul 30 2022 *)
  • PARI
    is(n)=my(f=factor(n)[,2]); n>9 && vecmax(f)!=lcm(f) \\ Charles R Greathouse IV, Oct 16 2015

Formula

A051903(a(n)) != A072411(a(n)).