For those without IML, something similar to Rick's program can be achieved using PROC SQL. Try the code below to generate the first 16 numbers of this type. Or replace 1000 with 9600 to extend the search to as far as an integer can be exactly represented under Windows. While n=1000 takes less than 1 second, n=9600 takes about 1 min on my machine.

data n;
do i=1 to 1000; output; end;
run;
;
proc sql;
create table t as
select a.i as i1, b.i as i2, i1**4 + i2**4 as s
from n a, n b where i1 < i2 order by s;
quit;
;
data _null_;
set t;
i3=lag(i1);
i4=lag(i2);
if s=lag(s) then put (i3 i4 i1 i2) (5.0) s comma22.0;
run;

**************** OUTPUT ******************
59 158 133 134 635,318,657
7 239 157 227 3,262,811,042
256 257 193 292 8,657,437,697
266 268 118 316 10,165,098,512
399 402 177 474 51,460,811,217
14 478 314 454 52,204,976,672
271 502 298 497 68,899,596,497
359 514 103 542 86,409,838,577
512 514 386 584 138,519,003,152
222 631 503 558 160,961,094,577
532 536 236 632 162,641,576,192
21 717 471 681 264,287,694,402
665 670 295 790 397,074,160,625
768 771 579 876 701,252,453,457
354 948 798 804 823,372,979,472
28 956 628 908 835,279,626,752