OFFSET
0,6
COMMENTS
a(n) mod 4=0.
LINKS
Indranil Ghosh and Chai Wah Wu, Table of n, a(n) for n = 0..10000 (terms for n = 0..240 from Indranil Ghosh)
PROG
(Python)
def t(n):
s=0
for a in range(n+1):
for b in range(n+1):
for c in range(n+1):
for d in range(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)==a+d:
s+=1
return s
for i in range(241):
print(str(i)+" "+str(t(i)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Indranil Ghosh, Nov 30 2016
STATUS
approved