Carmichael 3 strong pseudoprimes

func forprimes(a, b, callback) {
    for (a = (a-1 -> next_prime); a <= b; a.next_prime!) {
        callback(a)
    }
}

forprimes(3, 61, func(p) {
   for h3 in (2 ..^ p) {
      var ph3 = (p + h3)
      for d in (1 ..^ ph3) {
         ((-p * p) % h3) != (d % h3) && next
         ((p-1) * ph3) % d && next
         var q = 1+((p-1) * ph3 / d)
         q.is_prime || next
         var r = 1+((p*q - 1)/h3)
         r.is_prime || next
         (q*r) % (p-1) == 1 || next
         printf("%2d x %5d x %5d = %s\n",p,q,r, p*q*r)
      }
   }
})

Output:

 3 x    11 x    17 = 561
 5 x    29 x    73 = 10585
 5 x    17 x    29 = 2465
 5 x    13 x    17 = 1105
 ... full output is 69 lines ...
61 x   661 x  2521 = 101649241
61 x   271 x   571 = 9439201
61 x   241 x   421 = 6189121
61 x  3361 x  4021 = 824389441

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