From 3dd5b562e101535f202a914c57b7cafd2fcbf19d Mon Sep 17 00:00:00 2001
From: Daira Hopwood <daira@jacaranda.org>
Date: Sat, 26 Sep 2020 21:32:27 +0100
Subject: [PATCH] amicable.sage: the 2-adicity of p could be less than
 specified when using stretch (doesn't affect Tweedle curves).

Signed-off-by: Daira Hopwood <daira@jacaranda.org>
---
 amicable.sage | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/amicable.sage b/amicable.sage
index 917503c..050b616 100644
--- a/amicable.sage
+++ b/amicable.sage
@@ -16,7 +16,7 @@ DEFAULT_TWOADICITY = 32
 DEFAULT_STRETCH = 0
 
 COEFFICIENT_RANGE = (5,)
-#COEFFICIENT_RANGE = range(1, 10000)
+#COEFFICIENT_RANGE = range(1, 100)
 
 ACCEPTABLE_PRIMES = (5,)
 #ACCEPTABLE_PRIMES = Primes()
@@ -98,6 +98,9 @@ def symmetric_range(n, base=0, step=1):
 
 def find_nice_curves(strategy, L, twoadicity, stretch, wid, processes):
     for (p, T, V) in strategy(L, max(0, twoadicity-stretch), wid, processes):
+        if p % (1<<twoadicity) != 1:
+            continue
+
         sys.stdout.write('.')
         sys.stdout.flush()