V0715

by Michael Thomas De Vlieger, updated 18 December 2023, St. Louis, Missouri.

Name

Tantus k (in A126706) such that p₂ > q, i.e., A119288(k) > A053669(k).

Data

20, 28, 40, 44, 45, 50, 52, 56, 63, 68, 75, 76, 80, 88, 92, 98, 99, 100, 104, 112, 116, 117, 124, 135, 136, 140, 147, 148, 152, 153, 160, 164, 171, 172, 175, 176, 184, 188, 189, 196, 200, 207, 208, 212, 220, 224, 225, 232, 236, 242, 244, 245, 248, 250, 260, 261, 268, 272, 275, 279, 280, 284, 292, 296, 297, 304, 308, 315, 316, 320, 325, 328, 332, 333, 338, 340

Offset

1, 1

Comments

Theorem. Odd tantus k implies p₂ > q, i.e., (i.e., A360769 ⊂ V0705).
Proof. If k is odd, q = 2, and since primes must be divisors or not and 2 is the smallest prime, it follows that p₂ > q.

Links

Table of n, a(n) for n = 1..2^16.

Formula

This sequence is { k : Ω(m) > ω(m) > 1, p₂ > q }.

Example

a(1) = 20 since p₂ = 5 and q = 3.
a(2) = 28 since p₂ = 7 and q = 3.

Mathematica

Select[Range[12, 120], Function[{k, f},
  And[PrimeOmega[k] > PrimeNu[k] > 1,
  f[[2, 1]] > SelectFirst[Prime@ Range[PrimePi[f[[-1, 1]]] + 1],
    ! Divisible[k, #] &]]] @@
  {#, FactorInteger[#]} &] (* Michael De Vlieger, 18 December 2023 *)

Crossrefs

Cf. V7 = A126706, V0100 = A053669, V0111 = A002110, V0201 = A001221, V0202 = A001222, V0210 = A055932, V0716, V0701 = A360769, V0730 = A126706 ∩ A055932, V1002 = A119288.

Keyword

nonn, cnst, clas

Author Michael De Vlieger, Dec 18 2023

V-series integer sequences may or may not also appear in OEIS; these are used when either the sequence is a work in progress and has to do with constitutive matters, is still being researched, or does not merit general interest at OEIS.