A058198 Where d(m) (number of divisors, A000005) has risen by at least n.

2, 6, 12, 12, 24, 24, 48, 48, 60, 60, 120, 120, 168, 168, 180, 180, 240, 240, 360, 360, 360, 360, 720, 720, 720, 720, 720, 720, 840, 840, 1260, 1260, 1260, 1260, 1680, 1680, 2520, 2520, 2520, 2520, 2520, 2520, 2520, 2520, 3360, 3360, 5040, 5040, 5040, 5040

Offset: 1

Author

N. J. A. Sloane, Nov 28 2000

Keywords

• nonn
• nice
• easy

Comments

a(n) exists for all n (Turán, 1954). - Amiram Eldar, Apr 13 2024

a(n) >= A061799(n). - David A. Corneth, Apr 13 2024

Examples

			d(11) = 2, d(12) = 6 gives first jump of >= 3, so a(3) = a(4) = 12.
		

References

• József Sándor, Dragoslav S. Mitrinovic, and Borislav Crstici, Handbook of Number Theory I, Springer Science & Business Media, 2005, Chapter II, p. 39, section II.1.3.a.

Links

• David A. Corneth, Table of n, a(n) for n = 1..10000 (terms 1..1004 from T. D. Noe, terms 1005..2044 from Amiram Eldar)
• Pál Turán, Problem 71, Matematikai Lapok, Vol. 5 (1954), p. 48, entire volume; Solution to Problem 71, by Lajos Takács, ibid., Vol. 56, (1956), p. 154, entire volume.

Crossrefs

Equals A058197(n) + 1.

Cf. A000005, A051950, A058199, A061799.

Programs

Haskell

a058198 = (+ 1) . a058197  -- Reinhard Zumkeller, Feb 04 2013

Extensions

More terms from James Sellers, Nov 29 2000