• #### Strongest palindrome

From robertwalks@gmail.com@21:1/5 to Mark Brader on Sat Feb 15 17:27:28 2020
besides the self-palindromic ones you mentioned, at 12-digites there are the following palindromic pairs in the first 1,000,000 digits, from the same source you cite.
(Interesting there is only 1 12-digit repeating sequence, "756130190263" in the same set). Why are there 4 times more palindromes than repeats?

"826086201398"
"893102680628"

"450197791054" self

"324623125383"
"383521326423"

"404631767287"
"782767136404"

"475082805749"
"947508280574"

"383521326423" self

On Tuesday, May 21, 2019 at 10:31:04 PM UTC-4, Mark Brader wrote:
Gene Wirchenko:
You monster! Now you have me wondering what the longest
palindrome in the first 100,000 digits of pi is.

Assuming that http://www.angio.net/pi/digits/pi1000000.txt has the
correct digits, it'd be 0136776310, starting at the 16061st decimal
place.

I'm actually surprised that it's unique and that short. In the whole
million digits, there are 9 other palindroms of length 10 digits,
9 of length 11, one of length 12, and one of length 13. But all of
these are between the 240,000th and 940,000th decimal places.

(The two longest are 450197791054, at the 273,840th decimal place, and 9475082805749, at the 879,326th. A simple C program found all of these
in less than a second, then took half an hour to confirm that there are
no longer ones in the first million digits.)
--
Mark Brader, Toronto "Remember that computers are very, msb@vex.net very fast..." -- Steve Summit