A380432 Numbers k such that bigomega(k) > omega(k) > 3.

420, 630, 660, 780, 840, 924, 990, 1020, 1050, 1092, 1140, 1170, 1260, 1320, 1380, 1386, 1428, 1470, 1530, 1540, 1560, 1596, 1638, 1650, 1680, 1710, 1716, 1740, 1820, 1848, 1860, 1890, 1932, 1950, 1980, 2040, 2070, 2100, 2142, 2184, 2220, 2244, 2280, 2340, 2380

Offset

1,1

Comments

A200521 is a proper subset; a(144) = 4620 is not contained in A200521; A200521(144) = 4650.

Subset of A375055, which is in turn a subset of A126706.

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Example

Table of select a(n) showing exponents listed in columns of primes written vertically in the heading. For p^0 we instead write "." for clarity:
              Exponent of prime
                     1 1 1 1
   n   a(n)   2 3 5 7 1 3 7 9
  -----------------------------
    1    420   2 1 1 1
    2    630   1 2 1 1
    3    660   2 1 1 . 1
    4    780   2 1 1 . . 1
    5    840   3 1 1 1
    6    924   2 1 . 1 1
    7    990   1 2 1 . 1
    8   1020   2 1 1 . . . 1
    9   1050   1 1 2 1
   10   1092   2 1 . 1 . 1
   11   1140   2 1 1 . . . . 1
   12   1170   1 2 1 . . 1
  144   4620   2 1 1 1 1
  190   5460   2 1 1 1 . 1
  275   6930   1 2 1 1 1

Mathematica

Select[Range[2500], PrimeOmega[#] > PrimeNu[#] > 3 &]

Crossrefs

Cf. A001221, A001222, A126706, A200521, A375055.

Sequence in context: A069064 A024410 A200521 * A350374 A189982 A376374

Adjacent sequences: A380429 A380430 A380431 * A380433 A380434 A380435

Keyword

nonn,easy

Author

Michael De Vlieger, Jan 29 2025

Status

approved