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challenge - prime numbers where sum of squared digits of prime number is also prime
01-06-2018, 05:46 PM (This post was last modified: 01-07-2018 03:05 PM by wawa.)
Post: #12
RE: challenge - prime numbers where sum ...
Here is my program for the DM42/Free42/HP42s.
The DM42 gives the answer for 100000 in 4 minutes.
Type the limit in X, the program CHALNG returns the number of such primes in X and the last prime found with that property in Y.
Ex: 100000 -> X:1818 and Y: 99971
1000 -> X:53 and Y:997

Edit : On the true hp42s, the 1000 chalenge takes 8 minutes to complete. The 100000 is out of reach in a reasonable time.

Code:
00 { 239-Byte Prgm }
01▸LBL "PR?"
02 ENTER
03 ENTER
04 ENTER
05 2
06 MOD
07 X=0?
08 GTO 02
09 CLX
10 3
11 MOD
12 X=0?
13 GTO 02
14 CLX
15 5
16 MOD
17 X=0?
18 GTO 02
19 SIGN
20 SIGN
21▸LBL 01
22 X<> ST L
23 6
24 +
25 MOD
26 X=0?
27 GTO 02
28 X<> ST L
29 4
30 +
31 MOD
32 X=0?
33 GTO 02
34 X<> ST L
35 2
36 +
37 MOD
38 X=0?
39 GTO 02
40 X<> ST L
41 4
42 +
43 MOD
44 X=0?
45 GTO 02
46 X<> ST L
47 2
48 +
49 MOD
50 X=0?
51 GTO 02
52 X<> ST L
53 4
54 +
55 MOD
56 X=0?
57 GTO 02
58 X<> ST L
59 6
60 +
61 MOD
62 X=0?
63 GTO 02
64 X<> ST L
65 2
66 +
67 MOD
68 X=0?
69 GTO 02
70 X<> ST L
71 X↑2
72 X<Y?
73 GTO 01
74 R↓
75 SIGN
76▸LBL 02
77 CLX
78 LASTX
79 X<Y?
80 CLX
81 X=Y?
82 SIGN
83 END
84▸LBL "NPRM"
85 STO 06
86 2
87 X>Y?
88 RTN
89 MOD
90 X=0?
91 DSE 06
92▸LBL 01
93 RCL 06
94 2
95 +
96 STO 06
97 XEQ "PR?"
98 X=0?
99 GTO 01
100 RCL 06
101 END
102▸LBL "CHALNG"
103 STO 03
104 0
105 STO 02
106 STO 01
107 2
108▸LBL 00
109 STO 00
110 RCL 03
111 X<Y?
112 GTO 01
113 R↓
114 XEQ A
115 XEQ "PR?"
116 X=0?
117 GTO 02
118 VIEW 00
119 RCL 00
120 STO 02
121 ISG 01
122▸LBL 02
123 RCL 00
124 XEQ "NPRM"
125 GTO 00
126▸LBL 01
127 RCL 02
128 RCL 01
129 RTN
130▸LBL A
131 0
132 X<>Y
133▸LBL 10
134 RCL ST X
135 10
136 MOD
137 X↑2
138 STO+ ST Z
139 R↓
140 10
141 ÷
142 IP
143 X≠0?
144 GTO 10
145 X<>Y
146 RTN
147 END
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RE: challenge - prime numbers where sum ... - wawa - 01-06-2018 05:46 PM



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