Solution to Project Euler problem 97

extra/project-euler/097/097.factor

@@ -0,0 +1,31 @@
+! Copyright (c) 2008 Aaron Schaefer.
+! See http://factorcode.org/license.txt for BSD license.
+USING: math math.functions ;
+IN: project-euler.097
+
+! http://projecteuler.net/index.php?section=problems&id=97
+
+! DESCRIPTION
+! -----------
+
+! The first known prime found to exceed one million digits was discovered in
+! 1999, and is a Mersenne prime of the form 2^6972593 − 1; it contains exactly
+! 2,098,960 digits. Subsequently other Mersenne primes, of the form 2p − 1,
+! have been found which contain more digits.
+
+! However, in 2004 there was found a massive non-Mersenne prime which contains
+! 2,357,207 digits: 28433 * 2^7830457 + 1.
+
+! Find the last ten digits of this prime number.
+
+
+! SOLUTION
+! --------
+
+: euler097 ( -- answer )
+     2 7830457 10 10 ^ ^mod 28433 * 10 10 ^ mod 1+ ;
+
+! [ euler097 ] 100 ave-time
+! 0 ms run / 0 ms GC ave time - 100 trials
+
+MAIN: euler097

extra/project-euler/project-euler.factor

@@ -13,8 +13,8 @@ USING: definitions io io.files kernel math math.parser project-euler.ave-time
     project-euler.033 project-euler.034 project-euler.035 project-euler.036
     project-euler.037 project-euler.038 project-euler.039 project-euler.040
     project-euler.041 project-euler.042 project-euler.048 project-euler.052
-    project-euler.067 project-euler.075 project-euler.134 project-euler.169
-    project-euler.173 project-euler.175 ;
+    project-euler.067 project-euler.075 project-euler.097 project-euler.134
+    project-euler.169 project-euler.173 project-euler.175 ;
 IN: project-euler
 
 <PRIVATE