OFFSET
1,1
COMMENTS
The most frequent errors are:
- permutation between 2 ranks
- error in one rank
LINKS
Author?, Les-mathematiques.net [Broken link?]
EXAMPLE
Actual n is 97. It generates 74 errors.
Best choices could be 27, 54, 63, 81 or 99 instead of 97.
PROG
(Python)
for cle in range(1, 100):
n=0
for r1 in range(1, 14):
for r2 in range(r1, 14):
ur1=cle-(10**(13-r1))%cle
ur2=cle-(10**(13-r2))%cle
for c1 in range(10):
for c2 in range(10):
if c1==c2:
dif=1
else:
dif=(c1*ur1-c2*ur2)%cle
if dif==0:
n=n+1
print(cle, ':', n)
CROSSREFS
KEYWORD
fini,full,nonn
AUTHOR
Sébastien Dumortier, Apr 26 2008
STATUS
approved