multidigital number | Niven number

A positive integer which is divisible by the sum of its digits, also called a Niven number or a multidigital number. The first few are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 18, 20, 21, 24, ... (OEIS A005349). Grundman proved that there is no sequence of more than 20 consecutive Harshad numbers, and found the smallest sequence of 20 consecutive Harshad numbers, each member of which has 44363342786 digits. Grundman defined an n-Harshad (or n-Niven) number to be a positive integer which is divisible by the sum of its digits in base n>=2. Cai showed that for n = 2 or 3, there exists an infinite family of sequences of consecutive n-Harshad numbers of length 2n.