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 A027563 #13 Jan 09 2025 19:13:58 %S A027563 1,2,3,5,6,8,9,11,14,15,18,21,23,26,29,30,33,35,41,48,51,53,63,65,74, %T A027563 75,86,89,90,98,111,113,119,125,131,141,155,158,173,179,191,209,210, %U A027563 233,239,251,254,273,285,293,321,323,326,338,341,345,363,419 %N A027563 Numbers not of form abc + abd + acd + bcd for 1<=a<=b<=c<=d. %C A027563 This list is conjecturally complete, but this has not been proved. It may be complete as a consequence of the Generalized Riemann Hypothesis; see comments for A025052. - _Harry Richman_, Jan 09 2025 %H A027563 T. D. Noe, <a href="/A027563/b027563.txt">Table of n, a(n) for n=1..126</a> (complete sequence) %Y A027563 Cf. A025052 (3 variables), A027564 (5 variables), A027565, A027566. %K A027563 nonn,fini,full %O A027563 1,2 %A A027563 _R. H. Hardin_