triples.py

# greatest common divisor
from fractions import gcd

n = 100
# pre-compute squares
N = 15*n
L = [False]
L.extend([i**2 for i in range(1,N)])
rL = list()
    
for i in range(3,n+1):
    for j in range(i+1,N):
        if gcd(i,j) != 1:
            continue
        c_sq = L[i] + L[j]
        if c_sq in L:
            rL.append((i,j,L.index(c_sq)))

rL.sort()
for t in rL:
    a,b,c = t
    s = '%4d ' * 3
    print s % (a,b,c)

'''
> python triples.py > triples.txt
> cat triples.txt 
   3    4    5 
   5   12   13 
   7   24   25 
   8   15   17 
   9   40   41 
  11   60   61 
  12   35   37 
  13   84   85 
  15  112  113 
  16   63   65 
  17  144  145 
  19  180  181 
  20   21   29 
  20   99  101 
  21  220  221 
  23  264  265 
  24  143  145 
  25  312  313 
  27  364  365 
  28   45   53 
  28  195  197 
  29  420  421 
  31  480  481 
  32  255  257 
  33   56   65 
  33  544  545 
  35  612  613 
  36   77   85 
  36  323  325 
  37  684  685 
  39   80   89 
  39  760  761 
  40  399  401 
  41  840  841 
  43  924  925 
  44  117  125 
  44  483  485 
  45 1012 1013 
  47 1104 1105 
  48   55   73 
  48  575  577 
  49 1200 1201 
  51  140  149 
  51 1300 1301 
  52  165  173 
  52  675  677 
  53 1404 1405 
  56  783  785 
  57  176  185 
  60   91  109 
  60  221  229 
  60  899  901 
  64 1023 1025 
  65   72   97 
  68  285  293 
  68 1155 1157 
  69  260  269 
  72 1295 1297 
  75  308  317 
  76  357  365 
  76 1443 1445 
  84  187  205 
  84  437  445 
  85  132  157 
  87  416  425 
  88  105  137 
  92  525  533 
  93  476  485 
  95  168  193 
  96  247  265 
 100  621  629 
> 
'''