## Puzzle Archive

May 2020 Solution

The answer to this month’s puzzle is 416.

As suggested by the title, one number is expelled in each row.  The nth number in the nth row of the grid is expelled, and does not appear in any future rows.

In each successive row, the numbers are re-ordered.  Starting at the expelled number in row n-1, row n is generated by writing the numbers positioned (-1,1,-2,2,-3,3,-4,4,…) away from the expelled number, as long as they exist, where negative numbers mean “to the left” and positive numbers mean “to the right.”

The bottom grid displays, for each number 1 through 10, the number of the row where it is eventually expelled.  It is not until row 416 that the number 11 is finally expelled!  Most solvers wrote a quick program to compute this instead of running through it manually.   A program would have been essential if we had asked for the row where the number 48 is expelled!

Congratulations to everyone who solved this month’s puzzle!

Correct Submissions From:

Rahul Saxena
Miklós Horváth
Tim T.
Helen Yuan
Zihao Li
Stan Tendijck
arriopolis
Tanya Otsetarova
Orlin Kuchumbov
Monotof
Keith Schneider
Karl Mahlburg
Filip Vesovic
JamesJ
Cooper Young
Thomas.Mendez
Sergey Salnikov
Jack Dylan
Primusa
Ivan Galakhov
Matt Yang
Neil Thistlethwaite
Ananay22
Gordon Macshane
Sherwin
David Fair
Will Gulian
Willem Hoek
googlweknoall
Ben Reiniger
weineng
Sean Egan
tongssss
Glauber Guarinello
Dimas Ramos
gtyrovolas
Gee
Aaron Bryden
Wula
Jarry Xia
Oscar X.
Garrett Andersen
jakkap
Cubist
Mark Spindler
CPJ
micmic
Kristof S
Luka
Lawrence
kinder3141
martinobdl
Will Liao
Alex Kalbach
Sashalazz
Simon Behar
Joey Cimochowski
ssf0409
Christopher Wiriawan
Andi Qu
Guillaume C.
brianchen
MK
HonorableNed
Mukunth
Erik-Cristian Seulean
Jonah Goldstein
Ray Murphy
Sébastien Geeraert
Sandman
BingBong
zhelih
Giannis Tsaraias
Rachit Surana
Dan Lin
Alex Haoyi Xuan
Justin Knowles
Jin Kyu Lim
Aravind
nathanl3
Sandip Ghoshal
Scott Okuno
Hudson Vieira
Ian Sleightholme
debbiejeanlew
Song Pan
erbero
Mykyta Makovenko
Stranger
Angus King
PB
Guillermo Wildschut
Jaime Benabent
Aaron Naidu
jakab922
Leila
Edgar Wang
Ezio
Will Christerson
Sherry Sarkar
John Bostanci
Walter Sebastian Gisler
Clayton Bass
sniffleheim
Sean Lin
Dou Liu
Isaac Hildebrandt
Daniel Hathcock
Luke Thistlethwaite
vazae
Ahmed Shahbaz
Sergey Tychinin
Shubham Agrawal
Joe McGrath
Ryan Leung
John Bamford
Thibaut Montes
Glen High
Mattia Mariantoni
Felix Berief
Michal Mráz
Ivan Lakhtanov
pai
Arne Schneuing
Peter Brohan
pmmj
Simon Gee
Palo Margitfalvi & Karin Demkova
Kent Andrews
Kunming Wu
Alvin Jin
rlyapin
MP
Nigel Brumpton
Juli Szeto
Mario Di Dio
eugenedu
neilcalderon
Ayush Sachdeva
Leif
Tai Zong
Rodrigo Amorim
Rohit Mahankali
VenuGVangala
ttnb
n5d11
Sunny Lee
Domenico Bianco
Rohith Edupuganti
Andrew Milas
Zhen Zhou
JamesF
Waleed Malik
Jacob Gross
Alex Koshkarov
Katya Yakymenko
Senthil Rajasekaran
Dewei Chuan
Amogh Sood
Brian Yu
Bergmoney
Jeffrey Fu
Klein Chen
David Fluck
ZhiuTech
wbay
Vuk119
Anders Amundson
cathayc
MieMie_MONSTER
Kristopher Connett
Fernando Ramacciotti
Sam Lloyd
Nicolas Cherel
Mohamed Akbarally
Anastasija Ilic
Thomas Wheeler
imonday
Percy
Krisztian Sebestyen
Makalp Patel
Magister Mugit
Kashiwagi Yuki
Jaj Ludden
0101-1001
Iain
Manuel Sarmiento
Rishabh Singh
William YIP
nipiyng
Max Wilson
JamesY
NMS
Sanandan Sandman
aha
Hamza Irfan Bhatti
Ainnnia
Ryan Chua
cssachse
Darragh Keane
Jese Camilo
andylikescharli
MCJ
sjs
Danil Savine
Ariom
Scott Dudley
Matías Benzo
Asa Birch
juxej
Andrew Smith
Andrew T
Logan Weber
Ternanni
Thanks Healthcare Workers, First Responders, and Essential Workers!
Michael Jenkins
Atul Kr. Verma
George Wahid
alexeyvin
Christopher Vasiu
raahim salman
Marshall G
Jacoby Jaeger
Meredith T.
Arshad Huda & Zain Huda
Goh CJ
Zef Klop
Doveybenjamin
Harin Chong
Andy Liu
Heidi Stockton
Koren
Sasha Hydrie,Caroline Norman
Ken Knowles
KJA
samson
tiffwt
Gordon C
v. zhang
Andrew Tran
Douglas McGill
Ken Kwok
Alexander Schmolck
zyklotomic
marco lucchesi
vsabnis
Cameron and Brandon Hadfield
Alex Wice
Hans Enlin
Edward Gathuru
Mukund Subramaniam
Oleh Stolyar
Theo Tirel
Alexey Levin
Tatum & Tristan Kreindler
Dustin Riley
yayimahuman
Geoff Donoghue
Siddha Kilaru
cream
bing
Young Chen
Lance Li
Shawn Wu
Rafal Muszynski
Tanner Hoke
Quinn Bardwell
Paulina Tsai
Christopher Kei
Jules Kozolinsky
MateiS
AlbertCalmus
Jens K Vyff
Nadia Magnuson and Ben Visness
Shun R
Jason Ke
JFLF
Claude Koh Lanta
Sweta Dasgupta
Andrea Zhang
turtle
David Carcamo
Marouann
Calum
Pat Gardner
Pavle Vuksanovic
Richard Xu
CJ
Ethan Banks
Kyle Craig
Pavel Hudec