There is a simple two step pattern, not sure if that’s the one you’re looking for.
n1, n2=n1-2, n3=n2/2, n4=n3-2, n5=n4/2…
Leaving the next entry as 1.
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Nicely done Eoink.
That’s what I was looking for. Subtract 2; divide by 2; subtract 2; divide by 2 …
You might all like to try the next one …
What is the next number in the following series and how is the series constructed ?
2 4 13 26 35 70 ?
79, double, add 9, repeat.
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Well done Eoink.
I make it 2
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I get 2 as well.
I second that 
Well done guys. I think we can conclude it’s 2.
Integers decreasing 5, 4, 3, 2 … 1
Fractions increasing 1/5; 1/4; 1/3; 1/2 … 1/1
1 and 1/1 = 2
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What is the next number in the following series, or pattern of numbers and how is the series constructed ?
4; 5; 7; 9; 13; 15; 19; 21; ?
My interpretation was 1 x 1/1 = 1 
(because there is no plus sign and there is the use of the /, some I assumed it was a multiplication rather than an addition).
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I should have spotted this immediately, but I am no longer in the prime of my life
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Sad really, Ravvie.
But a couple of years ago, you would have been !!
Aaaggghh, it took the hint, obvious when you see it,
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Interestingly (or surprisingly ?), the newspaper in which I first saw that last teaser, gave the answer as 24 !!! They also started the sequence with 3.
Now, I always thought that 1 is not a prime number, so I have always started this sequence with 4. And of course the answer to the fundamental question isn’t 24.
The same newspaper (we are going back to my early days in the Trucial States '68 - '72) came up with 4; 6; 26; 666; ?
So, (I do so like starting questions with “so”) what is the next number in the above series, or pattern of numbers and how is the series constructed ?
I found this one a bit more difficult than the previous ones !
443546 if I’ve got the multiplication right. (I’ll explain the pattern when others have a go.)
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Hi Eoink,
The multiplication was probably right, but your addition/subtraction was initially wrong. However, I then noticed that you modified your result. So it looks like your +/- is starting to improve 
Well done.
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