%%MatrixMarket matrix coordinate integer symmetric
%-------------------------------------------------------------------------------
% UF Sparse Matrix Collection, Tim Davis
% http://www.cise.ufl.edu/research/sparse/matrices/JGD_Trefethen/Trefethen_20
% name: JGD_Trefethen/Trefethen_20
% [Diagonal matrices with primes, Nick Trefethen, Oxford Univ.]
% id: 2204
% date: 2008
% author: N. Trefethen
% ed: J.-G. Dumas
% fields: name title A id date author ed kind notes
% kind: combinatorial problem
%-------------------------------------------------------------------------------
% notes:
% Diagonal matrices with primes, Nick Trefethen, Oxford Univ.          
% From Jean-Guillaume Dumas' Sparse Integer Matrix Collection,         
% http://ljk.imag.fr/membres/Jean-Guillaume.Dumas/simc.html            
%                                                                      
% Problem 7 of the Hundred-dollar, Hundred-digit Challenge Problems,   
% SIAM News, vol 35, no. 1.                                            
%                                                                      
% 7. Let A be the 20,000 x 20,000 matrix whose entries are zero        
% everywhere except for the primes 2, 3, 5, 7, . . . , 224737 along the
% main diagonal and the number 1 in all the positions A(i,j) with      
% |i-j| = 1,2,4,8, . . . ,16384.  What is the (1,1) entry of inv(A)?   
%                                                                      
% http://www.siam.org/news/news.php?id=388                             
%                                                                      
% Filename in JGD collection: Trefethen/trefethen_20.sms               
%-------------------------------------------------------------------------------
20 20 89
1 1 2
2 1 1
3 1 1
5 1 1
9 1 1
17 1 1
2 2 3
3 2 1
4 2 1
6 2 1
10 2 1
18 2 1
3 3 5
4 3 1
5 3 1
7 3 1
11 3 1
19 3 1
4 4 7
5 4 1
6 4 1
8 4 1
12 4 1
20 4 1
5 5 11
6 5 1
7 5 1
9 5 1
13 5 1
6 6 13
7 6 1
8 6 1
10 6 1
14 6 1
7 7 17
8 7 1
9 7 1
11 7 1
15 7 1
8 8 19
9 8 1
10 8 1
12 8 1
16 8 1
9 9 23
10 9 1
11 9 1
13 9 1
17 9 1
10 10 29
11 10 1
12 10 1
14 10 1
18 10 1
11 11 31
12 11 1
13 11 1
15 11 1
19 11 1
12 12 37
13 12 1
14 12 1
16 12 1
20 12 1
13 13 41
14 13 1
15 13 1
17 13 1
14 14 43
15 14 1
16 14 1
18 14 1
15 15 47
16 15 1
17 15 1
19 15 1
16 16 53
17 16 1
18 16 1
20 16 1
17 17 59
18 17 1
19 17 1
18 18 61
19 18 1
20 18 1
19 19 67
20 19 1
20 20 71