A321505 Numbers k such that k and k+1 each have at least 5 distinct prime factors.

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

Author

M. F. Hasler, Nov 12 2018

Keywords

• nonn

Comments

Equals A140079 up to a(34) but a(35) = 728364 is not in A140079, see A321495.

Links

• M. F. Hasler, Table of n, a(n) for n = 1..10000

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).

Programs

Mathematica

Select[Range[750000], PrimeNu[#] > 4 && PrimeNu[# + 1] > 4 &] (* Amiram Eldar, Nov 12 2018 *)

PARI

is(n)=omega(n)>=5&&omega(n+1)>=5