[go: up one dir, main page]

login
A086975
Numbers of the form p^2 * q * r with primes p < q < r.
4
60, 84, 132, 140, 156, 204, 220, 228, 260, 276, 308, 315, 340, 348, 364, 372, 380, 444, 460, 476, 492, 495, 516, 532, 564, 572, 580, 585, 620, 636, 644, 693, 708, 732, 740, 748, 765, 804, 812, 819, 820, 836, 852, 855, 860, 868, 876, 884, 940, 948, 988
OFFSET
1,1
LINKS
FORMULA
A001221(a(n)) = 3.
A001222(a(n)) = 4.
A020639(a(n))^2 divides a(n).
A000005(a(n)) = 12. - Amiram Eldar, Sep 15 2024
MATHEMATICA
Select[Range[1000], FactorInteger[#][[;; , 2]] == {2, 1, 1} &] (* Amiram Eldar, Sep 15 2024 *)
PROG
(PARI) is(k) = factor(k)[, 2] == [2, 1, 1]~; \\ Amiram Eldar, Sep 15 2024
CROSSREFS
Subsequence of A086974 and of A085987.
Sequence in context: A350140 A291125 A337688 * A357686 A100659 A069976
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 25 2003
STATUS
approved