My browser crashes so sorry i have to do this

sorry my browser crashes a lot so a picture is given of solution

All the perfect squares

sorry window crash a lot so i have to do this

Either n= 2^x   +1,2^x   +2

Proof
suppose n=2k+1
now after one round only k will be left with last one having 3 coins.if k is odd
then after 2 rounds you will arive at same situation .to end it k must be even.if not understood  if kth(supposing k is odd) will have 2 extra coins at end of round which  it have to pass but for now we stopped the round
then every one will go one through -1 +1…. and then  +1-1 nullifying effect no of coins wont chance because every one would have atleast 2 coins.

suppose n is 2k then after 1 round k-1 will be left with last one having 3 coins no k-1 will be 2^x   + 1  (read all what i have written before).n is 2^(x+1 )      +2

tuesday
all though i fail usually on that

20
he spent 70(60 + (80-70)) got 90

5 POINT STAR

Yes it is possible
a=b+c
b=d+e
c=f+g
d=h+i
e=j+k
f=l+m
g=n+o

Now suppose a is a middle number in 3 by 3 box
since any integer can be expressed as sum of two integers with infinite possibilities .following the above steps we  can understand a can be expressed as sum of h,I,j,k,l,m,n,o .with each variable having infinite possibiles.now at any point we can find infinite integers which can surround a satisfying given condition.this can be used for any number in the table.we will find 8 integers which we have not used .now expanding table we will never be restricted to choose one number for the numbers surrounding the boundaries of table there will at least be a option of choosing 2 now since we have used  limited numbers till now.there will be numbers having a required sum and uncommon with numbers we have used.so there will be no blockage in expanding our table

47 as there is still a case when we take 46 socks and 3 pairs are not there