A368780 - OEIS

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A368780

Cubefree numbers divisible by the square of their largest prime factor.

1

4, 9, 18, 25, 36, 49, 50, 75, 98, 100, 121, 147, 150, 169, 196, 225, 242, 245, 289, 294, 300, 338, 361, 363, 441, 450, 484, 490, 507, 529, 578, 588, 605, 676, 722, 726, 735, 841, 845, 847, 867, 882, 900, 961, 980, 1014, 1058, 1083, 1089, 1156, 1183, 1210, 1225

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

Rafael Jakimczuk, Some observations on the greatest prime factor of an integer, Annales Mathematicae Silesianae, Vol. 37, No. 1 (2023), pp. 67-81. See Theorem 2.2, p. 71.

MATHEMATICA

Select[Range[1500], Max[e = FactorInteger[#][[;; , 2]]] < 3 && e[[-1]] == 2 &]

PROG

(PARI) is(n) = {my(e = factor(n)[, 2]); n > 1 && vecmax(e) < 3 && e[#e] == 2; }

CROSSREFS

Intersection of A070003 and A004709 or A067259.

Sequence in context: A313358 A263351 A064599 * A062952 A344405 A229027

Adjacent sequences: A368777 A368778 A368779 * A368781 A368782 A368783

KEYWORD

nonn,easy

AUTHOR

Amiram Eldar, Jan 05 2024

STATUS

approved