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.

A164596 Squarefree positive integers n where at least one prime divisor of n is < the product of the smaller prime divisors of n.

Original entry on oeis.org

30, 70, 105, 154, 165, 182, 195, 210, 231, 273, 286, 330, 357, 374, 385, 390, 399, 418, 429, 442, 455, 462, 494, 510, 546, 561, 570, 595, 598, 627, 646, 663, 665, 690, 714, 715, 741, 759, 770, 782, 798, 805, 858, 870, 874, 897, 910, 930, 935, 957, 966, 969
Offset: 1

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Author

Leroy Quet, Aug 17 2009

Keywords

Comments

Each term is divisible by at least 3 primes.

Examples

			70 is factored as 2*5*7. Since 2*5 > 7, then 70 is in this sequence.
		

Programs

  • Mathematica
    aQ[n_] := SquareFreeQ[n] && Module[{p = FactorInteger[n][[;;,1]], ans = False}, Do[If[p[[k]] < Times @@ p[[1 ;; k-1]], ans = True; Break[]], {k, 1, Length[p]}]; ans]; Select[Range[1000], aQ] (* Amiram Eldar, Oct 06 2019 *)

Extensions

More terms from Max Alekseyev, Sep 04 2009