|
|
A058198
|
|
Where d(m) (number of divisors, A000005) has risen by at least n.
|
|
4
|
|
|
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
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
a(n) exists for all n (Turán, 1954). - Amiram Eldar, Apr 13 2024
|
|
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
|
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.
|
|
EXAMPLE
|
d(11) = 2, d(12) = 6 gives first jump of >= 3, so a(3) = a(4) = 12.
|
|
PROG
|
(Haskell)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,nice,easy,changed
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|