fine the missing

[pkavitha]

Find the missing Term 4, 8, 28, 80, 244

[Gizmonster]

728

[Gizmonster]

Forgot to post explanation .....

difference between each number alternates .... firstly it's x3 and -4, then it's x3 and +4 ..... then back to x3 and -4 .....

(4 x 3) -4 = 8

(8 x 3) + 4 = 28

(28 x 3) - 4 = 80

(80 x 3) + 4 = 244

(244 x 3) - 4 = 728

[sp1214]

I think its 180

4............8..........28.........80........180........244
.......4...........20.........52........116........
..............16..........32.........64...........128......ie doubling up

[Gizmonster]

sp1214 yours doesn't quite add up .....

it works for the first few numbers:

4 ............ 8 ........... 28 ........... 80 ...........
....... 4 ........... 20 ........... 52 .............
............... 16 .......... 32 ..........

but for the next number on the bottom line to be 64, the sequence now reads:

4 ............ 8 ........... 28 ........... 80 ........... 196 ..............
........ 4 ........... 20 ........... 52 .......... 116 ............
............... 16 .......... 32 .......... 64 ............

we know that the next number on the top line is 244, so now the sequence reads:

4 ............ 8 ........... 28 ........... 80 ........... 196 .............. 244
....... 4 ........... 20 ........... 52 .......... 116 ............ 48
.............. 16 .......... 32 .......... 64 ............ -68

It's close, but it doesn't quite work with the last few numbers.

If the last number was 440 instead of 244, then it would work okay:

4 ............ 8 ........... 28 ........... 80 ........... 196 .............. 440
....... 4 ........... 20 ........... 52 .......... 116 ............ 244
.............. 16 .......... 32 .......... 64 ............ 128

I wonder if pkavitha has made a typo, cos it's weird how the last number on the 2nd line would be 244 ...... anyway my works so either I'm right (hopefully lol) or pkavitha made a typo and you're right .......