|
| |
|
|
A246532
|
|
Smallest Meertens number in base n, or -1 if none exists.
|
|
2
|
|
|
|
2, 10, 200, 6, 54, 100, 216, 4199040, 81312000, -1, -1, -1, 47250, -1, 18, 36
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
2,1
|
|
|
COMMENTS
|
A Meertens number in base n is a fixed point of the base n Godel encoding.
The base n Godel encoding of x is 2^d(1) * 3^d(2) * ... * prime(k)^d(k), where d(1)d(2)...d(k) is the base n representation of x.
The -1 entries are all conjectures.
In a computer search that included all numbers < 10^29 and bases <= 16, the only additional Meertens numbers found were 6 (base 2), 10 (base 2), 49000 (base 5), and 181400 (base 5).
There is no base 11 Meertens number < 11^44 ~= 6.6*10^45.
There is no base 12 Meertens number < 12^40 ~= 1.4*10^43.
There is no base 13 Meertens number < 13^39 ~= 2.7*10^43.
There is no base 15 Meertens number < 15^37 ~= 3.2*10^43.
Other terms: a(17) = 36, a(19) = 96, a(32) = 256, a(51) = 54. - Chai Wah Wu, Aug 28 2014
All terms are even.
If n > 2 and a(n) != -1, then a(n) > n.
a(2*3^m-m) = 2*3^m for all m >= 0, i.e., a(n) > 0 for an infinite number of values of n.
Other terms: a(64) = a(4096) = 65536, a(71) = 216, a(160) = 324, a(323) = 1296, a(1455) = 2916, a(1942) = 5832, a(7775) = 46656, a(8294) = 82944, a(13118) = 26244.
(End)
Named by Bird (1998) after the Dutch computer scientist Lambert Meertens (b. 1944). - Amiram Eldar, Jun 23 2021
|
|
|
LINKS
|
|
|
|
EXAMPLE
|
100 is a base 7 Meertens number because 100 = 202_7 = 2^2 * 3^0 * 5^2.
4199040 is a base 9 Meertens number because 4199040 = 7810000_9 = 2^7 * 3^8 * 5^1.
|
|
|
CROSSREFS
|
Cf. A189398 (base 10 Godel encoding), A110765 (base 2 Godel encoding).
|
|
|
KEYWORD
|
sign,more
|
|
|
AUTHOR
|
|
|
|
EXTENSIONS
|
|
|
|
STATUS
|
approved
|
| |
|
|
