login
A321505
Numbers k such that k and k+1 each have at least 5 distinct prime factors.
6
254540, 310155, 378014, 421134, 432795, 483405, 486590, 486794, 488565, 489345, 507129, 522444, 545258, 549185, 558789, 558830, 567644, 577940, 584154, 591260, 598689, 627095, 634809, 637329, 663585, 666995, 667029, 678755, 687939, 690234, 707420, 712425, 720005, 720290, 728364, 743589
OFFSET
1,1
COMMENTS
Equals A140079 up to a(34) but a(35) = 728364 is not in A140079, see A321495.
LINKS
MATHEMATICA
Select[Range[750000], PrimeNu[#] > 4 && PrimeNu[# + 1] > 4 &] (* Amiram Eldar, Nov 12 2018 *)
PROG
(PARI) is(n)=omega(n)>=5&&omega(n+1)>=5
CROSSREFS
Cf. A140079 (variant with "exactly 5"), A321495 (terms not in A140079).
Cf. A321504 (analog for k=4 prime factors), A321506 (analog for k=6).
Sequence in context: A069176 A253725 A140079 * A034631 A168352 A147579
KEYWORD
nonn
AUTHOR
M. F. Hasler, Nov 12 2018
STATUS
approved