

One form of   Pythagorean quadruples   is   (for positive integers   a,   b,   c,   and   d):



    a2   +   b2   +   c2     =     d2 


An example:

    22   +   32   +   62     =     72 
 which is:
    4    +   9    +   36     =     49 


Task

For positive integers up   2,200   (inclusive),   for all values of   a,  
b,   c,   and   d,

find   (and show here)   those values of   d   that   can't   be represented.

Show the values of   d   on one line of output   (optionally with a title).



Related tasks

   Euler's sum of powers conjecture. 
   Pythagorean triples.


Reference

   the Wikipedia article:   Pythagorean quadruple.


squares <- d <- seq_len(2200)^2
aAndb <- outer(squares, squares, '+')
aAndb <- aAndb[upper.tri(aAndb, diag = TRUE)]
sapply(squares, function(c) d <<- setdiff(d, aAndb + c))
print(sqrt(d))