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 A287793 #5 May 31 2017 22:57:46
%S A287793 0,1,2,3,4,5,6,7,8,7,6,5,4,3,2,1,2,3,4,5,6,7,8,9,8,7,6,5,4,3,2,3,4,5,
%T A287793 6,7,8,9,10,9,8,7,6,5,4,3,4,5,6,7,8,9,10,11,10,9,8,7,6,5,4,5,6,7,8,9,
%U A287793 10,11,12,11,10,9,8,7,6,5,6,7,8,9,10,11
%N A287793 Eight steps forward, seven steps back.
%H A287793 <a href="/index/Rec#order_16">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-1).
%F A287793 a(n) = Sum_{i=1..n} (-1)^floor((2*i-2)/15).
%F A287793 a(n) = a(n-1) + a(n-15) - a(n-16) for n > 15.
%p A287793 A287793:=n->add((-1)^floor((2*i-2)/15), i=1..n): seq(A287793(n), n=0..200);
%t A287793 Table[Sum[(-1)^Floor[(2 i - 2)/15], {i, n}], {n, 0, 100}]
%Y A287793 Cf. A008611 (one step back, two steps forward).
%Y A287793 Cf. A058207 (three steps forward, two steps back).
%Y A287793 Cf. A260644 (four steps forward, three steps back).
%Y A287793 Cf. A271800 (five steps forward, four steps back).
%Y A287793 Cf. A271859 (six steps forward, five steps back).
%Y A287793 Cf. A287655 (seven steps forward, six steps back).
%K A287793 nonn,easy
%O A287793 0,3
%A A287793 _Wesley Ivan Hurt_, May 31 2017