This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
1560 = 41^2-11^2 = 43^2-17^2 = 71^2-59^2 = 83^2-73^2 = 197^2-193^2
840 = 31^2-11^2 = 37^2-23^2 = 41^2-29^2 = 47^2-37^2 = 73^2-67^2 = 107^2-103^2
Take[Transpose[Select[Tally[Sort[Last[#]-First[#]&/@(Subsets[ Prime[ Range[ 2000]],{2}]^2)]],Last[#]==6&]][[1]],40] (* Harvey P. Dale, Nov 17 2013 *)
1848 = 47^2-19^2 = 53^2-31^2 = 73^2-59^2 = 83^2-71^2 = 157^2-151^2 = 233^2-229^2 = 463^2-461^2.
7728 = 97^2-41^2 = 107^2-61^2 = 113^2-71^2 = 173^2-149^2 = 283^2-269^2 = 487^2-479^2 = 647^2-641^2 = 1933^2-1931^2
9240 = 97^2-13^2 = 101^2-31^2 = 103^2-37^2 = 107^2-47^2 = 127^2-83^2 = 131^2-89^2 = 179^2-151^2 = 467^2-457^2 = 2311^2-2309^2
21840 = 149^2-19^2 = 151^2-31^2 = 157^2-53^2 = 179^2-101^2 = 223^2-167^2 = 281^2-239^2 = 379^2-349^2 = 467^2-443^2 = 787^2-773^2 = 1097^2-1087^2
10920 = 107^2-23^2 = 109^2-31^2 = 113^2-43^2 = 131^2-79^2 = 151^2-109^2 = 197^2-167^2 = 223^2-197^2 = 283^2-263^2 = 397^2-383^2 = 461^2-449^2 = 2731^2-2729^2
55440 = 239^2-41^2 = 257^2-103^2 = 283^2-157^2 = 307^2-197^2 = 353^2-263^2 = 359^2-271^2 = 421^2-349^2 = 523^2-467^2 = 1549^2-1531^2 = 1987^2-1973^2 = 2777^2-2767^2 = 3469^2-3461^2