15/10/12 18:26:36.88 oc4xuXaB.net
>>4(2) Io
f := method(s,
b := list(1, 3, 2, 6, 4, 5)
c := 0
n :=s size - 1
for(i, 0, n,
if(s at(i) - 48 != 0,
for(j, i, n,
r := 0
for(k, 0, j - i,
r = r + (s at(j - k) - 48) * b at(k % 6)
)
if(r % 7 == 0, c = c + 1)
)
)
)
c
)
Io> f("20151012")
==> 1
Io> f("1234567890"repeated(10))
==> 681