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.
%I A316489 #8 Aug 03 2018 04:31:19 %S A316489 4,12,20,28,36,44,52,60,68,76,92,100,108,124,132,148,172,188,220,268, %T A316489 292,388,412 %N A316489 Positive numbers of the form 8*k + 4 that cannot be expressed as the sum of four distinct odd squares. %C A316489 There are no more terms through 10^11. It seems extremely unlikely that any more terms exist. %C A316489 Every odd square is a number of the form 8*k + 1, so every sum of four odd squares is a number of the form 8*k + 4. %C A316489 A316834 lists all numbers that can be expressed in only one way as the sum of four distinct odd squares. %Y A316489 Cf. A316834. %K A316489 nonn %O A316489 1,1 %A A316489 _Jon E. Schoenfield_, Jul 27 2018