|
|
A318242
|
|
a(n) is the least k such that A188999(A188999(k)) = n*k, where A188999 is the bi-unitary sigma function, or 0 if no such k exists.
|
|
1
|
|
|
1, 2, 8, 15, 24, 42, 240, 648, 168, 480, 321408, 4320, 57120, 103680, 1827840, 23591520, 898128000, 374250240
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
It is also known that a(20) = 11975040.
Then for higher indices n, we have:
a(19) <= 5235707393280;
a(21) <= 49110437376000;
a(22) <= 106780561395056640;
a(24) <= 1099525819392000;
a(25) <= 41252767395840;
a(26) <= 202768780032000.
|
|
LINKS
|
|
|
CROSSREFS
|
Cf. A272930 (analog for sigma), A318272 (analog for infinitary sigma).
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|