euler 049 solution

euler0XX/euler049.py

@@ -0,0 +1,19 @@
+from itertools import combinations, permutations
+from numbertools import is_prime
+
+answers = set()
+for n in range(1000, 10000):
+    perms = {int(''.join(p)) for p in permutations(str(n))}
+
+    # remove permutations with less than 4 digits (leading 0) and that are not prime
+    perms = {p for p in perms if p >= 1000 and is_prime(p)}
+
+    if len(perms) < 3:
+        continue
+
+    for a, b, c in combinations(perms, r=3):
+        if a - b == b - c:
+            answers.add((a, b, c))
+
+for a, b, c in answers:
+    print(f'{a}{b}{c}')