|
|
A007295
|
|
Number of elements (a b, c d) in GL(2,Z) with |det| = 1, trace <= n and 0 <= a <= {b, c} <= d.
|
|
2
|
|
|
1, 2, 4, 8, 11, 18, 22, 30, 36, 48, 53, 67, 74, 87, 100, 120, 125, 145, 155, 179, 193, 215, 227, 255, 273, 303, 317, 339, 356, 404, 416, 444, 463, 506, 525, 567, 592, 624, 647, 707, 725, 769, 797, 833, 866, 904, 928, 1008, 1026, 1086, 1125, 1171, 1189, 1247, 1283
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
Example from Neven Juric, Apr 21 2008: a(5) = 11 from the matrices (0 1, 1 1), (0 1, 1 2), (0 1, 1 3), (0 1, 1 4), (0 1, 1 5), (1 1, 1 2), (1 1, 2 3), (1 1, 3 4), (1 2, 1 3), (1 2, 2 3), (1 3, 1 4).
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
John Lewis (frc.mass.edu)
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|