Math ∩ Programming

Here are some more whimsical OEIS sequences I came across. XKCD 2016 joked that "OEIS keeps rejecting my submissions," including one that gives "Integers in increasing order of width when printed in Helvetica." Well, two days after that comic was publishe

Table of Contents In this tutorial series, I will introduce the CKKS homomorphic encryption scheme from the ground up, in rather intricate detail. Each article in this series corresponds to a pull request on a GitHub repository. The code for this article

I went hunting for references to the OEIS in open source code, and found some weird ones. There are not one, but two live-coding music frameworks that use OEIS sequences as a source for "anything that can be sequenced" in music. I'm guessing that's used f

A051070 is a sequence about OEIS sequences. a(n) is the n-th term in sequence A_n (or -1 if A_n doesn't have enough terms). So the first term in A051070 is 1 because A000001 is the number of groups of order n, and that sequence has 1 as its entry in index

Problem: Determine if a 32-bit number is prime (deterministically) Solution: (in C++) // Bases to test. Using the first 4 prime bases makes the test deterministic // for all 32-bit integers. See https://oeis.org/A014233. int64_t bases = {2, 3, 5, 7}; inli

It's the 5th annual April Cools! Here are my previous April Cools articles This year it's a book review of Ben Recht's book, The Irrational Decision: How We Gave Computers the Power to Choose For us, released Mar 10, 2026. The publishing industry has a st

In an earlier article, I covered the basic technique for performing matrix-vector multiplication in fully homomorphic encryption (FHE), known as the Halevi-Shoup diagonal method. This article covers a more recent method for matrix-matrix multiplication kn

Polyhedral optimization is a tool used in compilers for optimizing loop nests. While the major compilers that use this implement polyhedral optimizations from scratch,1 there is a generally-applicable open source C library called the Integer Set Library (

On Monday, July 14th 2025, I hosted a mini-workshop on homomorphic encryption at Google's Portland, Oregon office. Though Portland is a small city, it's becoming a hub for homomorphic encryption. Intel and Google both have a presence here, as well as the

I work on homomorphic encryption (HE or FHE for "fully" homomorphic encryption) and I have written a lot about it on this blog (see the relevant tag). This article is a collection of short answers to questions I see on various threads and news aggregators