OFFSET
0,8
LINKS
Indranil Ghosh and Chai Wah Wu, Table of n, a(n) for n = 0..10000 (terms n = 0..200 from Indranil Ghosh)
PROG
(Python)
def a(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 abs(a*d-b*c)==1:
s+=1
return s
print([int(a(n)/8) for n in range(0, 52)]) # Indranil Ghosh, Nov 30 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Indranil Ghosh, Nov 30 2016
STATUS
approved