Update to recently found large Mersenne prime.

examples/perfnum.cc

@@ -9,8 +9,9 @@ using namespace cln;
 int main ()
 {
 	// previous ones were 1257787, 1398269, 2976221, 3021377, 6972593,
-	// 13466917, 20996011, 24036583, 25964951, 30402457, 32582657, 37156667
-	int p = 43112609;
+	// 13466917, 20996011, 24036583, 25964951, 30402457, 32582657, 37156667,
+	// 42643801, 43112609
+	int p = 57885161;
 	cl_I x = (((cl_I)1 << p) - 1) << (p-1);
 	cout << x << endl;
 }