hard sequences

Whim

no ideas?


Whim

<Quote>no ideas? </Quote>
No time - no ideas. Later.

Whim

#16:

A, CB, EDC, GFED, IHGFE

Don't quite know how to describe it... Each sequence is one letter longer than the last, terminating in the next letter in the alphabet.

15. 281761830, ?, 2417101826, ?, 2017141822

281761830, 261781828, 2417101826, 2217121824, 2017141822

Easier to see if you write it out as:

28 17 6 18 30, 26 17 8 18 28 , 24 17 10 18 26, 22 17 12 18 24 , 20 17 14 18 22

14. ?, 911, ?, 79, 68, ?

1012,911,810,79,68,57

Similar to 15:

10 12, 9 11, 8 10, 7 9, 6 8, 5 7

12. ?, ?, ?, 61, 96, 35, 109, 166, 57

appears to be in the format:
a1,b1,c1,a2,b2,c2,a3,b3,c3

c2=b2-a1 and c3=b3-a3, so I think we can conclude that c1=b1-a1, which give a series like:

a1, b1, b1-a1, a2, b2, b2-a2, a3, b3, b3-a3

I haven't found any relations between a2 and a3 or b2 and b3. (possibly b3=b2+2(c2), but that doesn't get me anywhere)

19. ?, 1920212223, ?,301122131415061798, 910111213, 012345678

31242125112601279181, 1920212223, 1415161718, 301122131415061798, 910111213, 012345678

Works like this:

Looking at the last in the sequence, we see that it is simply counting up, starting with 0. Next to last in the sequence starts counting up starting with the next number, second item in sequence counts up starting with 19. Therefore, the third item should count upward and end with 18. Furthermore, if we count back down we find that it starts with 14, which fits with what we see in the fifth place.

(it might be easier to see if we reverse the sequence: 012345678, 910111213, ignore, 1415161718, 1920212223, ignore)

This leaves us with the last empty place to fill.

If we reorder our sequence back to the original we have: ?, 1920212223, 1415161718, 301122131415061798, 910111213, 012345678

After staring at the fourth item in the sequence for a while (and reading previous posts), I realized it is spiral counting again.

Looking at item four, it is the last number in five, followed by the first number in six, then the next-to-last number in five, then the second number in six, etc.

Great work!

Can you repost the ones which haven't been answered? I never saw the first 10.

21. ?, 0233, ?, 010336, 7141122, 46876218
22. ?, ?, 33322224444433, 222554444333
23. ?, ?, ?, 92114136158, 910111213141516, 12345678
24. ?, ?, 1212, ?, 2456, ?, 3101, 6748, 9647
25. ?, 68714, 46988531, 96382, 86787, ?, 84563, ?, 34273265, ?, 12345
26. 211066, ?, 439115, 314569,
27. C, 1B4, D, ?, ?, 1B2, ?, 1B1
28. 521, ?, 58, 25, 13, 2, ?, ?
29. ?, MGEACIK, ?, EAC, A
30. ?, 31, 43, 41, 75, 35, 92, ?, 83

27. C, 1B4, D, ?, ?, 1B2, ?, 1B1

C, 1B4, D, 1B3, E, 1B2, F, 1B1

Looks to be counting in Hexidecimal (or higher base number).

C=12, 1B4=436=1C0-C, D=13, 1B3=435=1C0-D, E=14, 1B2=434=1C0-E, F=15, 1B1=433=1C0-F

29. ?, MGEACIK, ?, EAC, A

Spiral counting with letters

OMGEACIKQ, MGEACIK, GEACI, EAC, A

Reverse the series:

A, EAC, GEACI, MGEACIK, OMGEACIKQ

On each item, add two letters from the series C E G I K M O Q..... First add to the right end, then the left end. Next add to the right end then the left end, next add to the left end then the right end, etc.

23. ?, ?, ?, 92114136158, 910111213141516, 12345678

Reverse the sequence:

12345678, 910111213141516, 92114136158, ?, ?, ?

I see this pattern:

01 02 03 04 05 06 07 08,

09 10 11 12 13 14 15 16,

09 02 11 04 13 06 15 08,
?,
?,
?

I don't see enough internal logic to allow you to continue the series.

You could make the assumption that it has the format: a1=f(seedvalue), b1=f(a1), c1=f(a1, b1), a2, b2=f(a2), c2=f(a1, b1)

a2 could be of several formats, however: 23456789 or 13579111315 or 1718192021222324 or any number of other series.