OEIS sequence

This Sequence implementation allows access to any integer sequence in the Online Encyclopedia of Integer Sequences (OEIS). Note that the specific sequence in the Encyclopedia represented by this sequence is determined at the time the sequence is created with the Sequence Switcher. In other words, the sequence ID (A000040 in the example depicted above, corresponding to the sequence of prime numbers) is not a parameter, and cannot be changed once the sequence is created. To view a sequence in the OEIS, open the Sequence Switcher (by clicking on the box where the sequence name appears in the Sequence tab). It will show a list of possible sequences, with previews of your current visualizer operating on them. Some of them will be OEIS sequences. If you see the sequence you want, just click on it.

If not, enter any term related to the sequence (or just the ID of the sequence itself if you know it), and a list of matching sequences will come up. Click on the description of the sequence you want (clicking on its ID goes to the corresponding page in the OEIS), and it will be added to the list of sequences to preview, adding a thumbnail to the popup gallery. Now you can click on that preview to start visualizing with your desired sequence.

One other note about OEIS sequences: your browser must download the entry values from the web. So although much of Numberscope will operate offline once you've fully loaded its page, if you want to visualize an OEIS sequence you will need an active internet connection.

Parameters

  • Modulus: Since many visualizers work best when the input is in a restricted range, or just because you might be interested in examining a sequence with respect to modulo-m arithmetic for some m, you can specify this "modulus" parameter. If you do, each entry of the OEIS sequence will be divided by this modulus, and only the remainder from that division will be sent to the visualizer as the entry value. If you don't specify the modulus or set it to 0, the OEIS sequence values will be used unchanged.

Plus the standard parameters for all formulas:

  • First index: the first index of the sequence to use in visualization. Many sequences have a smallest available index; if so, that number will be the default value for thus parameter. Otherwise, the default will be zero.
  • Last index: the index of the last entry of the sequence to use in visualization. Similarly, many sequences have a largest available index, which will become the default value for this parameter. If not, the default is Infinity, which means that the visualizer may continue to request more and more terms indefinitely.
  • Number of terms: the number of terms of the sequence to use in visualization. Of course, the number of terms must be the last index, minus the first index, plus one. So this parameter and the previous two can not actually be independently set. What will happen in practice is that changing any one of them will automatically change the value of one of the others to keep things consistent. The default value for this parameter is determined by the first and last index.