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C
#include <stdio.h>

int main()
{
    int i, j, k, l;
    
    for (i = 1; i <= 5; i++)
    {
        for (j = 5; j > i; j--)
        {
            printf(" ");
        }
        for (k = i; k >= 1; k--)
        {
            printf("%d", k);
        }
        for (l = 2; l <= i; l++)
        {
            printf("%d", l);
        }
        printf("\n");
    }

    return 0;
}
Source

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