|
| |
|
|
A374091
|
|
a(n) is the smallest nonnegative integer k where exactly n ordered pairs of positive integers (x, y) exist such that x^2 + 3*x*y + y^2 = k.
|
|
3
|
|
|
|
0, 5, 11, 605, 209, 73205, 2299, 8857805, 6061, 218405, 278179
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
COMMENTS
|
a(n) is the smallest nonnegative k such that A374089(k) = n.
a(n) is of the form 5*k^2 if and only if n is odd.
a(12) = 66671.
a(14) = 5285401.
a(15) = 26427005.
a(16) = 187891.
a(18) = 1266749.
a(20) = 8067191.
a(24) = 2066801.
a(26) = 36735721.
|
|
|
LINKS
|
|
|
|
FORMULA
|
a(n) <= 5*11^(n-1) for all n >= 1. - Jason Yuen, Jun 29 2024
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn,more
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
