Find the next number in this series:

503, 507, 550...

Maybe you'd want to pay close attention to the tags


The maker always leaves his trademark or stamp on it.


When you can't find the answer, look back at the source

  • $\begingroup$ (There don't appear to be any characters out of the ordinary in the source of this post - everything is ASCII, no zero-width characters or lookalikes or anything weird like that. And nothing weird about the source either.) $\endgroup$
    – Deusovi
    Commented Sep 4, 2019 at 18:12
  • $\begingroup$ @Deusovi rot13(npghnyyl, gurer vf, nobhg gur fbhepr) $\endgroup$ Commented Sep 4, 2019 at 18:14
  • $\begingroup$ Whatever you're referring to, I don't see it - the source directly reflects what's in the post, and I copied it into a text editor so I could check for weird characters with regex. $\endgroup$
    – Deusovi
    Commented Sep 4, 2019 at 18:18
  • $\begingroup$ @Deusovi, I could have justified myself, but if I do, the answer will be clear. I have already told you more than required, Sorry. $\endgroup$ Commented Sep 4, 2019 at 18:20
  • $\begingroup$ @Deusovi I don't think its weird characters, rot13(V pbhyq or jebat ohg vfa'g gurer rkprff bs punenpgre gb gur abez?) But I don't know what it means. $\endgroup$
    – Abbas
    Commented Sep 4, 2019 at 18:20

2 Answers 2


Long shot but here we go

The next number is 557

In the OP's response in the comments,

@Deusovi rot13(npghnyyl, gurer vf, nobhg gur fbhepr)


the source refers to both
   a) the source of the question (the OP) and
   b) the source code of the web page

Following the first one by...

visiting the OP's profile page

we are greeted by the following message

Look Closely See nearby
Here lies the way
(to the next hintswer (hint+answer))
a puzzle is lost on this website
use me to know if your'e right

Following this we..

..click on the nearby Activity tab

On the new page we can now apply the 2nd sense of OP's comment above or by paying close attention to the...

HTML tags (or source code)

Doing a Ctrl+F here we can see that 503, 507, and 550 appears in code that plots the OP's reputation on a graph.

However, 530 and 540 are smack in between 507 and 550. My flimsy theory is that the OP just hovered on the actual generated graph and missed these two values.

I know this guess is walking on thin ice but I've spent too much time not to post an answer! :P

  • $\begingroup$ You got it! I think the hint was too obvious. Well done! $\endgroup$ Commented Sep 6, 2019 at 10:46

Don't slate me if this is wrong but 559? First ever puzzle attempt!

  • 1
    $\begingroup$ What is your reasoning behind it? $\endgroup$ Commented Sep 6, 2019 at 10:38
  • $\begingroup$ Welcome to Puzzling SE, try answering using spoiler tags ( >! ) the next time. $\endgroup$ Commented Sep 6, 2019 at 10:41
  • $\begingroup$ Could you please elaborate? $\endgroup$ Commented Sep 6, 2019 at 10:42
  • $\begingroup$ sorry i feel i need to work out exactly how to remove spoilers now first $\endgroup$ Commented Sep 6, 2019 at 10:45
  • $\begingroup$ now I have finally got the tags to work - apologies for not doing it earlier! >! It is in your source code there is a specific tag id which is the next in the sequence $\endgroup$ Commented Sep 6, 2019 at 11:02

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