|
|
A278377
|
|
Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant n with no elements repeated.
|
|
1
|
|
|
0, 0, 0, 4, 8, 16, 40, 36, 72, 60, 128, 92, 232, 144, 260, 284, 332, 252, 564, 324, 680, 568, 696, 492, 1184, 628, 984, 964, 1392, 796, 1920, 924, 1820, 1512, 1752, 1568, 2820, 1380, 2244, 2104, 3340, 1660, 3864, 1900, 3544, 3388, 3300, 2264, 5652, 2632, 4616
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,4
|
|
LINKS
|
|
|
PROG
|
(Python)
def p(n):
s=0
for a in range(0, n+1):
for b in range(0, n+1):
for c in range(0, n+1):
for d in range(0, n+1):
if (a!=b and a!=d and b!=d and c!=a and c!=b and c!=d):
if a*d-b*c==n:
s+=1
return s
for i in range(0, 101):
|
|
CROSSREFS
|
Cf. A210282 (where the matrix elements can be repeated).
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|