In how many positive four-digit integers that are not multiples of 1111 do the digits form an arithmetic sequence from left to right?
1234 9876 5432
1357 9753 4321
2345 9630 3210
2468 8765
3456 8642
3579 7654
4567 7531
5678 6543
6789 6420
I count 21......anyone have a different result ????
