Below are 2 different sequences, but the rules are the same,
2, 3, 3, 9, 9, ?
3, 7, 3, 3, 7, 9, ?
determine the two missing numbers and find the rule,
Bonus. how far can each sequence go? Can you find a longer sequence of numbers that follow the same rule?
(In reply to
UBASIC program and complete list by Charlie)
As the ends of the branches contain all the information leading to them, there's no point in showing all the steps that lead to one end of a branch, so here is a cleaner complete list:
23333
23339
23399339
2393
2399333
29399999
31193
31379
317
37337999
373393
37397
3793
3797
53
59393339
593993
599
719333
7331
73331
73939133
7393931
7393933
739397
739399
797
made with the modified UBASIC program:
10 for S=1 to 9
20 gosub *Build(S)
30 next
40 end
100 *Build(N)
101 local J
110 if nxtprm(N-1)=N then
120 :if nxtprm(10*N)>10*N+10 then print N:endif
130 :for J=1 to 9 step 2
140 :gosub *Build(N*10+J)
150 :next
170 return
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Posted by Charlie
on 2004-12-19 15:47:29 |
Cleaner list
