5
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Getting bored of all the sequences (including mine)?

Here is a little different one for you.

What is the last one in the following:

C, H, O, P, S, ?

Tell me why?

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  • 2
    $\begingroup$ Is the no-computers tag necessary? $\endgroup$ – Brandon_J Jun 6 at 1:23
  • 1
    $\begingroup$ People can search for patterns just they do in oeis..that’s why I put it in..anyway most of my sequences wont be found in oeis. $\endgroup$ – Uvc Jun 6 at 1:31
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    $\begingroup$ But OEIS is the online encyclopedia of integer sequences, and this is not an integer sequence. $\endgroup$ – Brandon_J Jun 6 at 1:32
  • $\begingroup$ That would be a computer search..anyway I err on the side of caution . $\endgroup$ – Uvc Jun 6 at 1:34
12
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I think the answer is

N

Reasoning

These are chemical symbols representing the six most important chemical elements whose covalent combinations make up most biological molecules on Earth ("six elements of life"): carbon, hydrogen, oxygen, phosphorus, sulphur, nitrogen

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    $\begingroup$ Any explanation for the order? (i.e. why wasn't it H, C, ?, O, P, S in the puzzle?) $\endgroup$ – Rand al'Thor Jun 5 at 14:50
  • $\begingroup$ @Randal'Thor My thinking was that it's supposed to read as a word: CHOPS $\endgroup$ – hexomino Jun 5 at 14:53
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    $\begingroup$ I didn’t want it to be obvious and also like hexoomino says, I needed a nice sounding word rather than random letters. $\endgroup$ – Uvc Jun 5 at 15:09
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    $\begingroup$ Without giving a spoiler, this distribution exhibits bias towards a certain, umm, planet... $\endgroup$ – smci Jun 6 at 15:15
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    $\begingroup$ @smci Unless you can name another planet with its own kind of <spoiler-redacted>, it's not really bias :) $\endgroup$ – chepner Jun 6 at 17:25
16
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The answer is indeed

N for Nitrogen

but let me take a stab at the title:

$3^2 + 2^3 + 2^2 = 21$; "guesses" more or less sounds as "gas is" so "21 gas is left". Air consists of 79% Nitrogen and 21% other gasses.

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    $\begingroup$ Great find..but it is unintended correct coincidence..my reasoning was there are only 21 letters left..I just put it mathematically for fun.. $\endgroup$ – Uvc Jun 5 at 15:28
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    $\begingroup$ wow, almost seemed impossible to be a coincidence! $\endgroup$ – George Menoutis Jun 7 at 8:45
7
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This is a long shot, but the title could be a hint towards it.

W

because

3, 8, 15, 16, 19, 23, ... is the sequence of numbers whose base-5 representation contains no 2's and exactly one 3. (OEIS.)

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  • 1
    $\begingroup$ I heeded your suggestions and went non-mathematical for a change..title Is just a fancy way of expressing two neighbors. $\endgroup$ – Uvc Jun 5 at 14:53
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    $\begingroup$ Sometimes you wonder how such a sequence found its way to OEIS... $\endgroup$ – Evargalo Jun 5 at 14:53
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    $\begingroup$ @Evargalo Everything is on OEIS, I guess. $\endgroup$ – Rand al'Thor Jun 5 at 14:54
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    $\begingroup$ Not really..I developed more than 100 sequences specifically not to be found in oeis for mainly security management and cryptographic purposes. $\endgroup$ – Uvc Jun 5 at 15:00
  • 2
    $\begingroup$ @Uvc Huh??? All answers, including those about sequences, should be based on facts. $\endgroup$ – Rand al'Thor Jun 5 at 15:13
5
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According to the answer of hexomino I would say

N

Because

This is the writing order of chemical formula according to the Hill System, where atoms in molecules have to be named in this particular order.

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  • $\begingroup$ Right, but that's just a consequence (of the pattern mentioned by @hexomino et al.) rather than a cause. $\endgroup$ – smci Jun 6 at 15:14

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