>>119 #include <stdio.h> int f(int n) { int m, s; if (n < 10) return n == 1; for (s = 0; n; n /= 10) { m = n % 10; s += m * m; } return f(s); } int main(void) { int n; for (n = 1; n <= 10000; n++) if (f(n)) printf("%d ", n); printf("\n"); return 0; }