Data commit

Task/Unprimeable-numbers/Sidef/unprimeable-numbers.sidef

@@ -0,0 +1,32 @@
+func is_unprimeable(n) {
+    var t = 10*floor(n/10)
+    for k in (t+1 .. t+9 `by` 2) {
+        return false if k.is_prime
+    }
+
+    if (n.is_div(2) || n.is_div(5)) {
+        return true if !is_prime(n%10)
+        return true if (n % 10**n.ilog(10) > 9)
+    }
+
+    for k in (1 .. n.ilog(10)) {
+        var u = 10**k
+        var v = (n - (u * (floor(n/u) % 10)))
+        0..9 -> any {|d| is_prime(v + d*u) } && return false
+    }
+
+    return true
+}
+
+with (35) {|n|
+    say ("First #{n} unprimeables:\n", is_unprimeable.first(n).join(' '))
+}
+
+with (600) {|n|
+    say ("\n#{n}th unprimeable: ", is_unprimeable.nth(n), "\n")
+}
+
+for d in (0..9) {
+    say ("First unprimeable that ends with #{d}: ",
+        1..Inf -> lazy.map {|k| k*10 + d }.grep(is_unprimeable).first)
+}