Something

#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char * argv[])
{
        int i;
        int nrb[26];

        if (strlen(argv[1]) != 26)
                perror("wrong account numer: not 26 digts long");

        const int mod[] = {1, 10, 3, 30, 9, 90, 27, 76, 81, 34, 49, 5, 50, 15, 53, 45, 62, 38, 89, 17, 73, 51, 25, 56, 75, 71, 31, 19, 93, 57};

        for (i = 0; i < 27; i++) {
                nrb[i] = argv[1][i];
                printf("%c %li\n", argv[1][i], nrb[i]);
        }
}