Data commit

Task/Blum-integer/Python/blum-integer.py

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+''' python example for task rosettacode.org/wiki/Blum_integer '''
+
+from sympy import factorint
+
+
+def generate_blum():
+    ''' Generate the Blum integers in series '''
+    for candidate in range(1, 10_000_000_000):
+        fexp = factorint(candidate).items()
+        if len(fexp) == 2 and sum(p[1] == 1 and p[0] % 4 == 3 for p in fexp) == 2:
+            yield candidate
+
+
+print('First 50 Blum integers:')
+lastdigitsums = [0, 0, 0, 0]
+
+for idx, blum in enumerate(generate_blum()):
+    if idx < 50:
+        print(f'{blum: 4}', end='\n' if (idx + 1) % 10 == 0 else '')
+    elif idx + 1 in [26_828, 100_000, 200_000, 300_000, 400_000]:
+        print(f'\nThe {idx+1:,}th Blum number is {blum:,}.')
+
+    j = blum % 10
+    lastdigitsums[0] += j == 1
+    lastdigitsums[1] += j == 3
+    lastdigitsums[2] += j == 7
+    lastdigitsums[3] += j == 9
+
+    if idx + 1 == 400_000:
+        print('\n% distribution of the first 400,000 Blum integers is:')
+        for k, dig in enumerate([1, 3, 7, 9]):
+            print(f'{lastdigitsums[k]/4000:>8.5}% end in {dig}')
+
+        break