Fix "first D" to deal with "0"s; compare values with sieve, hund_div

First D algorithm stuff from
<http://dx.doi.org/10.1090/S0025-5718-1980-0583518-6> - if the Jacobi
(D/n) is 0, D is a factor of n.

lucas.py

@@ -2,6 +2,7 @@
 from math import sqrt, gcd, floor, log
 from time import process_time
 from psimp import trd, hund_div
+from sieve import sieve
 
 def isqrt(n):
     """ Find the integer square root of n via newton's method, code via
@@ -92,10 +93,15 @@ def FirstD(n):
     # square
     haschecked = False
     for D in Dsequence():
-        if Jacobi(D, n) == -1:
+        Jv = Jacobi(D, n)
+        # What we're looking for
+        if Jv == -1:
             return D
-        # This is supposed to be faster
-        if D > 30 and not haschecked:
+        # Have found a factor
+        if Jv == 0 and abs(D) != n:
+            return 0
+        # Check for square at 13
+        if D > 10 and not haschecked:
             if hasIntSQRT(n):
                 return 0
     # Shouldn't fire
@@ -234,21 +240,12 @@ def StrongLucasPrime(n):
 
 
 
-#print(StrongLucasPrime(7))
-
-np = 0
-
-for i in range(10000):
+mp = 400000
+ap = sieve(mp)
+for i in range(mp):
+    iip = i in ap
     lp = StrongLucasPrime(i)
-    if lp:
-        np = np + 1
-        print("{}:\t{};\t{}".format(i, lp, np))
-
-print(np)
-
-print(StrongLucasPrime(5459))
-print(hund_div(5459))
-print(StrongLucasPrime(5777))
-print(hund_div(5777))
+    if iip != lp:
+        print(iip, lp, i, hund_div(i), sep='\t')