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 A269445 #5 Feb 29 2016 03:00:40
%S A269445 0,0,0,0,0,0,0,0,0,0,0,0,0,1,2,3,4,5,6,7,8,9,10,11,12,13,15,17,19,21,
%T A269445 23,25,27,29,31,33,35,37,39,42,45,48,51,54,57,60,63,66,69,72,75,78,82,
%U A269445 86,90,94,98,102,106,110,114,118,122,126,130,135,140,145,150,155,160,165,170,175
%N A269445 a(n) = Sum_{k=0..n} floor(k/13).
%C A269445 Partial sums of A090620.
%C A269445 More generally, the ordinary generating function for the Sum_{k=0..n} floor(k/m) is x^m/((1 - x^m)*(1 - x)^2).
%H A269445 <a href="/index/Rec#order_15">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,0,0,0,0,0,0,0,0,0,0,1,-2,1).
%F A269445 G.f.: x^13/((1 - x^13)*(1 - x)^2).
%F A269445 a(n) = 2*a(n-1) - a(n-2) + a(n-13) - 2*a(n-14) + a(n-15).
%t A269445 Table[Sum[Floor[k/13], {k, 0, n}], {n, 0, 73}]
%t A269445 LinearRecurrence[{2, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -2, 1}, {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2}, 74]
%Y A269445 Cf. A090620.
%Y A269445 Cf. similar sequences of Sum_{k=0..n} floor(k/m): A002620 (m=2), A130518 (m=3), A130519 (m=4), A130520 (m=5), A174709 (m=6), A174738 (m=7), A118729 (m=8), A218470 (m=9), A131242 (m=10), A218530 (m=11), A221912 (m=12), this sequence (m=13).
%K A269445 nonn,easy
%O A269445 0,15
%A A269445 _Ilya Gutkovskiy_, Feb 27 2016