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.

A362584 Integers k > 1 such that k >= the square of the sum of their prime factors (A074373(k)).

Original entry on oeis.org

243, 256, 270, 288, 300, 320, 324, 336, 360, 375, 378, 384, 400, 405, 420, 432, 441, 448, 450, 480, 486, 490, 495, 500, 504, 512, 525, 528, 540, 550, 560, 567, 576, 585, 588, 594, 600, 616, 624, 625, 630, 640, 648, 650, 660, 672, 675, 686, 693, 700, 702, 704
Offset: 1

Views

Author

Simon R Blow, Jun 23 2023

Keywords

Examples

			243 >= A001414(243)^2 = (3+3+3+3+3=15)^2 = 225 so 243 is a term.
800 >= A001414(800)^2 = (2+2+2+2+2+5+5=20)^2 = 400 so 800 is a term.
		

Crossrefs

Programs

  • Maple
    q:= n-> n>=add(i[1]*i[2], i=ifactors(n)[2])^2:
    select(q, [$2..800])[];  # Alois P. Heinz, Jun 23 2023
  • Mathematica
    Select[Range[2, 700], # >= (Plus @@ Times @@@ FactorInteger[#])^2 &] (* Amiram Eldar, Jun 24 2023 *)
  • PARI
    isok(n) = ((p=factor(n))[, 1]~*p[, 2])^2 <= n \\ Thomas Scheuerle, Jun 23 2023