Christmas (2015) is coming!

This year, the front page of will feature an advent calendar. Behind each door, there will be a puzzle with a three digit solution.
As you solve the puzzles, your answers will be stored in a cookie. Behind the door on Christmas Day, there will be a form allowing you to submit your answers. The first person to submit the correct answers will win this array of prizes:
The prizes include an t-shirt, a DVD of Full Frontal Nerdity and a beautiful 2015 winner's medal:
I will be adding to the pile of prizes throughout December.
The next nine people to submit the correct answers will win a winner's medal plus a smaller goody bag of prizes. If less than ten correct entries are submitted, prizes will be given to those with one incorrect answer, then those with two incorrect answers and so on.
Each day's puzzle (and the entry form on Christmas Day) will be available from 5:00am GMT.
To win a prize, you must submit your entry before the start of 2016. Only one entry will be accepted per person. Once ten correct entries have been submitted, I will add a note here and below the calendar. If you have any questions, ask them in the comments below or on Twitter.
So once December is here, get solving! Good luck and have a very merry Christmas!
Edit: The winners and answers can now be found here.

Similar posts

Christmas (2019) is coming!
Christmas (2018) is over
Christmas (2018) is coming!
Christmas (2017) is over


Comments in green were written by me. Comments in blue were not written by me.
@Anonymous2: Other winners and answers will be available from 1st January
How many wrong answers do I have ? And when will you publish the solutions ?
@Anonymous1: You are (now) correct and on the leaderboard. Well done!
I've submitted my answer! On Christmas too! It's just that I sorta crammed all of the answers today :/

Are you allowed to tell me if I am correct?
I'm so glad for OEIS.

hint hint
 Add a Comment 

I will only use your email address to reply to your comment (if a reply is needed).

Allowed HTML tags: <br> <a> <small> <b> <i> <s> <sup> <sub> <u> <spoiler> <ul> <ol> <li>
To prove you are not a spam bot, please type "median" in the box below (case sensitive):


Show me a random blog post

Feb 2020

PhD thesis, chapter ∞
PhD thesis, chapter 5
PhD thesis, chapter 4
PhD thesis, chapter 3
Inverting a matrix
PhD thesis, chapter 2

Jan 2020

PhD thesis, chapter 1
Gaussian elimination
Matrix multiplication
Christmas (2019) is over
▼ show ▼
▼ show ▼
▼ show ▼
▼ show ▼
▼ show ▼
▼ show ▼
▼ show ▼
▼ show ▼


matrices sport numerical analysis trigonometry sorting national lottery platonic solids games propositional calculus big internet math-off mathslogicbot programming dragon curves finite element method statistics data weak imposition london ucl python inverse matrices matrix of minors news folding tube maps rhombicuboctahedron matrix multiplication dataset folding paper triangles hats manchester martin gardner talking maths in public draughts golden ratio european cup countdown rugby map projections noughts and crosses final fantasy arithmetic twitter christmas card radio 4 craft error bars nine men's morris speed phd hannah fry braiding royal institution palindromes latex inline code gerry anderson football frobel hexapawn sobolev spaces puzzles tmip geometry flexagons sound electromagnetic field bempp the aperiodical realhats asteroids preconditioning stickers computational complexity graph theory bodmas estimation game of life binary php machine learning cambridge logic people maths matt parker dates approximation reddit probability video games signorini conditions tennis advent calendar oeis javascript determinants golden spiral ternary manchester science festival harriss spiral menace accuracy pythagoras pac-man gaussian elimination a gamut of games raspberry pi go christmas wave scattering captain scarlet reuleaux polygons data visualisation misleading statistics fractals interpolation bubble bobble matrix of cofactors boundary element methods books cross stitch plastic ratio mathsteroids game show probability world cup chebyshev pizza cutting london underground wool royal baby light weather station curvature polynomials chalkdust magazine mathsjam chess simultaneous equations coins


Show me a random blog post
▼ show ▼
© Matthew Scroggs 2012–2020