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 A020962 #19 Jul 06 2019 13:47:02
%S A020962 1,3,8,22,55,137,334,812,1965,4751,11476,27714,66915,161557,390042,
%T A020962 941656,2273369,5488411,13250208,31988846,77227919,186444705,
%U A020962 450117350,1086679428,2623476229,6333631911,15290740076
%N A020962 a(n) = Sum_{k >= 1} floor((1+sqrt(2))^(n-k)).
%H A020962 C. Kimberling, <a href="https://www.jstor.org/stable/2975195">Problem 10520</a>, Amer. Math. Mon. 103 (1996) p. 347.
%F A020962 a(n) = Sum_{i=0..n-1} A080039(i).
%t A020962 Table[Sum[Floor[(1 + Sqrt[2])^(n - k)], {k, Infinity}], {n, 1, 27}] (* _Alonso del Arte_, Nov 30 2010 *)
%Y A020962 Cf. A080039.
%K A020962 nonn
%O A020962 1,2
%A A020962 _Clark Kimberling_
%E A020962 Revised Feb 03 1999. Revised Nov 30 2010.