SOLUTION: Consider the sequence of composite numbers: 4,6,8,9,10,12,14,15,16... Find: a. S3 b. S5 c. S12

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Question 1192833: Consider the sequence of composite numbers: 4,6,8,9,10,12,14,15,16...
Find:
a. S3
b. S5
c. S12
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52803)   (Show Source): You can put this solution on YOUR website!
.

Your sequence is the sequence of all natural numbers, starting from 2, with all prime numbers EXCLUDED.


So, you can restore your sequence on your own as far as you want (or, at least, to have 12 terms in front of you).


Next,


S3 is the sum of the first 3 terms.


S5 is the sum of the first 5 terms.


S12 is the sum of the first 12 terms.



You do the rest.

Solved  (which means that you got all necessary instructions from me . . . )

---------------

Ignore the post by @josgarithmetic,  since it is  IRRELEVANT.



Answer by josgarithmetic(39620)   (Show Source): You can put this solution on YOUR website!
pattern appears to be, +2, +2, +1, +1, then repeats. You can find what comes next.
Do sum as you need to.
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