A Tribute To Numberphile: Visualizing Recamán’s Sequence in VEX

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One of my favorite Youtube Channels is Numberphile. They are one of the driving forces behind my newfound interest in maths. In a recent video they shed some light onto a sequence of numbers called Recamán’s Sequence.

The amazing part here was the visualization that they developed for Recamán’s sequence: A beautiful pattern of semicircles that result from tracing the sequence’s jumps on a number line.
In this tutorial we’ll generate Recamán’s sequence and then visualize it using VEX only.

Download Project file

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  1. Bob Douglas

    Moritz, this is both elegant and potent in it capacity to generate a beautiful visualisation of the Recamán Sequence. Thank you for your lucid explanation.
    Do you think it is possible to extend the method by generating points in n-dimensional space?
    Starting with 4-D, one could conceivably navigate throughout neighbouring regions of such a space and visualise this journey by generating 3-D cross-sections.
    Perhaps though the probability of revisiting a point may become too small in which case one could define a region instead.

  2. Michele Spaliviero

    Hi Mo,
    sorry I came late to the party, I still hope you could help me! I followed all the instructions but at the end this error comes up on the “addprim” string:

    “No matching function for addprim(int; string; int[]). Candidates are: int addprim(int; string) (33,13:19).”

    Could you help me solve this? I’d much appreciate it!


    • Hi Michele,

      which Houdini version are you running? Also did you check the scene file we provide? Did that work?


  3. Hello,
    Thank you for this amazing tutorial in vex, it just blew me away!
    As far as I am a beginner in vex and that I have know Houdini for a year from now, I don’t exactly understand how it works entirely yet, and could you tell me how is it possible to add some new geometry splines to the others that you have done please?
    I watched the tutorial twice and some others about initiation to vex, but I don’t really get it, sorry.
    Thank you anyway for this stunning work!

    • Hi Delphine,

      have you watched Manu’s tutorial on geometry creation in VEX?

      He’s going over the basics there. If I understood your question correctly – here’s how you add splines to your current geo stream in VEX:

      1. If you want to create a spline using new points, first create those points using the addpoint() function.
      2. Create the lines using the addprim() function with the type argument set to “polyline”

      … and that’s about it 🙂


      • Hello, Moritz,

        Thank you so much for your reply. I had not watched the tutorial of Manuel yet, but I will, thanks!
        I will keep working on my side in order to improve my skills and see what I can do with it.

        Thank you again for you nice help.


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