Blog
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Pour Le Science and the anti-Sum-Product Problem
In March 2021, I got an out-of-the-blue email from OEIS editor Michel Marcus which totally delighted me. He wrote: This afternoon I went to the library.And I was browsing “Pour La Science” the French version of the Scientific American.And here…
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Zimin Words and Bifixes
One of the earliest contributions to the On-Line Encyclopedia of Integer Sequences (OEIS) was a family sequences counting the number of words that begin (or don’t begin) with a palindrome: Let \(f_k(n)\) be the number of strings of length \(n\)…
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My Favorite Sequences: A263135
This is the fourth in my installment of My Favorite Sequences. This post discusses sequence A263135 which counts penny-to-penny connections among \(n\) pennies on the vertices of a hexagonal grid. I published this sequence in October 2015 when I was…