A368780 Cubefree numbers divisible by the square of their largest prime factor.

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

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.

Cf. A006530.

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