A358647 Final digit reached by traveling right (with wraparound) through the digits of n. Each move steps right k places, where k is the digit at the beginning of the move. Moves begin at the most significant digit and d moves are made, where d is the number of digits in n.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 1, 4, 1, 6, 1, 8, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 3, 2, 3, 4, 3, 6, 3, 8, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 5, 2, 5, 4, 5, 6, 5, 8, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 0, 7, 2, 7, 4, 7, 6, 7, 8, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 0, 9, 2, 9, 4, 9, 6, 9, 8, 9

Offset

0,3

Links

Table of n, a(n) for n=0..99.

Moosa Nasir, Example of n = 11323.

Example

For n = 11323, start at the most significant digit, which is 1.
On move 1, travel 1 unit right, reaching the second digit 1.
On move 2, travel 1 unit right, reaching the middle digit 3.
On move 3, travel 3 units right (wrapping around), reaching the most significant 1 digit again.
On move 4, travel 1 unit right, reaching the second digit 1 (again).
On move 5, travel 1 unit right, reaching the middle digit 3 (again).
Thus, a(11323) = 3.

Prog

(C++)
int a(int n)
{
    int n2 = n;
    int size = 0; do { n2 /= 10; size++; } while (n2 != 0);
    int * nums = new int[size];
    for(int i = size - 1; i >= 0; i--)
    {
        nums[i] = n % 10;
        n /= 10;
    }
    int currentIndex = 0;
    for (int j = 0; j < size; j++)
    {
        currentIndex += nums[currentIndex];
        currentIndex %= size;
    }
    int returnVal = nums[currentIndex];
    delete[] nums;
    return returnVal;
}
(Python)
def A358647(n):
    s = list(map(int, str(n)))
    l, i = len(s), 0
    for _ in range(l):
         i = (i+s[i])%l
    return s[i] # Chai Wah Wu, Nov 30 2022

Crossrefs

Cf. A357531 (stepping in 1..n).

Sequence in context: A338379 A004426 A262188 * A004430 A285094 A134778

Adjacent sequences: A358644 A358645 A358646 * A358648 A358649 A358650

Keyword

nonn,base,easy

Author

Moosa Nasir, Nov 24 2022

Status

approved