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 A054686 #21 Apr 30 2014 01:34:21
%S A054686 0,0,1,1,3,4,6,9,10,15,16,21,25,28,36,36,45,49,55,64,66,78,81,91,100,
%T A054686 105,120,121,136,144,153,169,171,190,196,210,225,231,253,256,276,289,
%U A054686 300,324,325,351,361,378,400,406,435,441,465,484,496,528
%N A054686 Multiset consisting of squares and triangular numbers.
%C A054686 Terms of A001110 occur twice. [_Reinhard Zumkeller_, Aug 03 2011]
%D A054686 Hofstadter, D. R., Fluid Concepts and Creative Analogies: Computer Models of the Fundamental Mechanisms of Thought, (together with the Fluid Analogies Research Group), NY: Basic Books, 1995. p. 15.
%H A054686 Reinhard Zumkeller, <a href="/A054686/b054686.txt">Table of n, a(n) for n = 1..10000</a>
%t A054686 stnos[max_]:=Module[{sqmax=Floor[Sqrt[max]],trmax=Floor[(Sqrt[ 8max+1]- 1)/2]}, Sort[Join[Range[0,sqmax]^2,Accumulate[Range[0,trmax]]]]]; stnos[ 528] (* _Harvey P. Dale_, Feb 06 2012 *)
%o A054686 (Haskell)
%o A054686 a054686_list = merge a000290_list a000217_list where
%o A054686 merge xs'@(x:xs) ys'@(y:ys)
%o A054686 | x <= y = x : merge xs ys'
%o A054686 | otherwise = y : merge xs' ys
%o A054686 -- _Reinhard Zumkeller_, Aug 03 2011
%o A054686 (PARI) upTo(lim)=vecsort(concat(vector(sqrtint(lim\1)+1,n,(n-1)^2),vector(floor(sqrt(2+2*lim)+1/2),n,n*(n-1)/2))) \\ _Charles R Greathouse IV_, Aug 04 2011
%Y A054686 Cf. A005214, A000217, A000290.
%K A054686 nonn,easy
%O A054686 1,5
%A A054686 _Michael Somos_, Apr 19 2000
%E A054686 Offset fixed by _Reinhard Zumkeller_, Aug 04 2011