Merge branch 'master' of https://github.com/HackspaceJena/project-euler

16/euler16.py

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+sum([int(x) for x in list(str(2**1000))])

20/euler20.py

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+import math
+sum([int(x) for x in list(str(math.factorial(100)))])

47/euler47.rkt

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+#lang racket
+
+(require math/number-theory)
+
+(define (primefactors x)
+  (if (prime? x)
+      (list x)
+      (for/or ((i (cons 2 (range 3 (+ 1 (ceiling (sqrt x))) 2)))
+               #:when (prime? i)
+               #:when (zero? (remainder x i)))
+        (cons i (primefactors (quotient x i))))))
+
+(define (recur x)
+  (if (and
+       (equal? (length (remove-duplicates (primefactors x))) 4)
+       (equal? (length (remove-duplicates (primefactors (+ x 1)))) 4)
+       (equal? (length (remove-duplicates (primefactors (+ x 2)))) 4)
+       (equal? (length (remove-duplicates (primefactors (+ x 3)))) 4))
+      x
+      (recur (+ x 1))))
+
+(recur 2)

48/euler48.py

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+str(sum([x**x for x in range(1,1001)]))[-10:]