I can see that the length of each missing subsequence is greater by one than the length of the previous one. But I can't figure out how to determine its start number.

  • $\begingroup$ Can you clarify what you are asking? $\endgroup$
    – Techidiot
    Commented Jan 5, 2017 at 18:49
  • $\begingroup$ I'm asking for the continuation of the sequence, i.e. the next element of it $\endgroup$
    – Photon
    Commented Jan 5, 2017 at 19:00
  • $\begingroup$ Do you know the answer? What if the sequence is incorrect? $\endgroup$
    – Techidiot
    Commented Jan 5, 2017 at 19:03
  • $\begingroup$ No, I don't know the answer $\endgroup$
    – Photon
    Commented Jan 5, 2017 at 19:04

1 Answer 1


The next values would be

21, 22, 28, 29, 30....

The reason for this

the pattern that repeats is i+pn, i+pn, 1+pn, 1+pn, i+pn, 1+pn, 1+pn repeat
where pn = previous number in the sequence
i's value in the sequence constantly increases by 1 so the next sequence would be
4+pn, 5+pn, 1+pn, 1+pn, 6+pn, 1+pn, 1+pn
15, 20, 21, 22, 28, 29, 30

  • $\begingroup$ Is there enough information in this sequence to justify this pattern? $\endgroup$
    – user20
    Commented Jan 5, 2017 at 20:10
  • $\begingroup$ @Emrakul I edited to show that the pattern continued from the numbers in the question. It was my best shot at trying to explain the sequence. $\endgroup$
    – Zachstein
    Commented Jan 5, 2017 at 20:14

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