# Carnival of Mathematics 141

Published by Ganit Charcha | Category - Math Events | 2017-01-09 07:02:50

We are glad to host the $141$th Carnival of Mathematics in December $2016$ after last months Carnival of
Mathematics 140 by Tom at Mathematics and Coding. Carnival of Mathematics is a monthly blogging round up that is organised by The Aperiodical.

We choose to host $141$th Carnival in December because $22$nd of this month is celebrated as National Mathematics Day of India. Indian legendary Mathematician Srinivasa Ramanujan was born on $22$nd December $1887$. In order to recognize his immense contribution towards Mathematics the Government of India has declared Ramanujan's birthday to be celebrated every year as the National Mathematics Day of India.

To start with let us first take a look into some interesting facts about number 141.

1. A crazy sequential representation of $141$ written in terms of $1$ to $9$ in increasing as well as
decreasing order (taken from http://arxiv.org/abs/1302.1479) is as follows $$141 = 1 + 2.3.4 + 5.6 + 7 + 89 = 9 + 87 + 6.5 + 4.3 + 2 + 1$$
2. $141 = 3.47$ is a semiprime ( a natural number that has only two prime factors, not necessarily
distinct) and $A001358(46) =141$, where the description of $A001358$ can be found here
{https://oeis.org/A001358}. Interestingly, prior to this we celebrated $129$th Carnival of Mathematics
and eventually $129$ was also a semi-prime.

We will now move on to the posts that make up this months carnival.

Mark Dominus shared with us a nice article titledsquare. His discourse is motivated by a magic square carved at the entrance of Parshvantha Temple at Khajuraho

John Cook shared with us a blog post An integral with a couple lessons which illustrates in context to computing definite integrals two principles very nicely - (1) keep in mind the distinction between a definition and a computational technique, and (2) you might not have to do as much work as it seems.

James Clare shared with us a blog post Everything’s Mixed Up. Can You Sort It All Out? that describes some beautiful riddles.

Peter has shared with us the post titled Why the Number Line Freaks Me Out. This is a nice post which describes different types of computable numbers starting from whole numbers and at the end of it has talked about non-computable numbers which can not be understood by human mind.

Artem Kaznatcheev has provided us with the link of his post Fusion and sex in protocells & the start of evolution which in a way justifies that Theoretical biology is becoming increasingly mathematized. Most exciting is the introduction of tools from theoretical computer science and the analysis of algorithms. Here these tools, along with broader themes from computation, are used to analyze if the fusing parts of sex are essential for getting evolutionary dynamics going. The post combines fundamental biology with some fun math while summarizing, criticising, and expanding on a recent preprint.

Lucy Rycroft-Smith has shared with us his blog post Mathemethics: the dark and desirable 007 side to numbers that refutes the argument that mathematics is useless, and explores some of the thrilling narratives around mathematical, desirable skills.

Lucy Rycroft-Smith has also directed us with another blog post Taming, claiming and reframing the beast of mathematics that describes the essence of what mathematics is very aptly.

MIke Lawler has directed us to a blog post titled Kaleidoscopic Fractals: Folding the Koch Snowflake that shows that Koch snowflake is good for generating fractals with folds.

Joel David Hamkins has shared a brilliant post showing There are no nondegenerate regular polygons in the integer lattice, except for squares. A related follow up post as mentioned by him can be found here http://jdh.hamkins.org/no-regular-polygons-in-the-hexagonal-lattice/ .

A niced eye opener is the post Math myth-busting some of our worst urban planning misconceptions with lots of nice examples.

Who have more sisters: boys or girls?
a nice puzzle shared to us by the author Rob Eastaway.This seemingly simple question/puzzle was first posed to the author by Hugh Hunt a couple of years ago.  The puzzle turns out to have a number of interesting twists - a couple of which haven't been resolved.  For example, how does the fact that girls tend to live longer than boys affect the answer?  It's not obvious - and might call for a computer simulation.

Another nice post we would like to make a mention of is.

This brings to an end of this edition of Carnival of Mathematics. Next Carnival of Mathematics will be hosted by Manan at