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 A123067 #11 Sep 08 2022 08:45:28
%S A123067 1,2,2,4,4,6,8,2,10,10,2,12,4,4,10,4,10,12,10,10,20,12,4,12,12,12,8,8,
%T A123067 8,24,8,0,24,12,8,10,24,12,6,12,14,38,8,8,32,18,8,4,8,20,20,16,12,16,
%U A123067 24,4,30,28,4,14,20,12,2,18,18,44,20,8,28,12,10,26,30,12,28,16,20,20,8,16,34
%N A123067 Theta series of the "Little Methuselah" quadratic form x^2 + 2*y^2 + y*z + 4*z^2.
%C A123067 The Little Methuselah form represents every integer from 1 to 30, but fails to represent 31. Every integer-valued positive definite ternary form not equivalent to it fails to represent some integer between 1 and 30. [Conway]
%D A123067 J. H. Conway, The Sensual (Quadratic) Form, M.A.A., 1997, pp. 81-82.
%e A123067 1 + 2*x + 2*x^2 + 4*x^3 + 4*x^4 + 6*x^5 + 8*x^6 + 2*x^7 + 10*x^8 + 10*x^9 + 2*x^10 + ...
%o A123067 (Magma) L:=LatticeWithGram(3, [2,0,0,0,4,1,0,1,8] ); T<q> := ThetaSeries(L,500); T;
%o A123067 (PARI) {a(n)= if(n<1, n==0, qfrep([2, 0, 0; 0, 4, 1; 0, 1, 8],n, 1)[n]*2)} /* _Michael Somos_, Oct 23 2006 */
%Y A123067 Cf. A123063, A123064, A123065, A123068.
%K A123067 nonn
%O A123067 0,2
%A A123067 _N. J. A. Sloane_, Sep 27 2006, corrected Oct 26 2006