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 A291502 #7 Jun 11 2025 00:58:23
%S A291502 -55,-55,-55,-55,-55,-55,-55,-55,-55,-60,-66,-72,-78,-84,-90,-96,-102,
%T A291502 -108,-114,-120,-126,-132,-138,-144,-150,-156,-162,-168,-174,-180,
%U A291502 -186,-192,-198,-204,-210,-216,-222,-228,-234,-240,-246,-252,-258,-264,-270,-276,-282,-288,-294,-300,-306,-312,-318,-324,-330,-336,-342,-348,-354,-360,-366,-372,-378,-384,-390,-396,-402,-408,-414,-420
%N A291502 The arithmetic function uhat(n,1,8).
%H A291502 Bela Bajnok, <a href="https://arxiv.org/abs/1705.07444">Additive Combinatorics: A Menu of Research Problems</a>, arXiv:1705.07444 [math.NT], May 2017. See Table in Section 1.6.4.
%F A291502 Conjectures from _Chai Wah Wu_, Jun 10 2025: (Start)
%F A291502 a(n) = 2*a(n-1) - a(n-2) for n > 11.
%F A291502 G.f.: x*(-x^10 - 5*x^9 + 55*x - 55)/(x - 1)^2. (End)
%t A291502 delta[r_, k_, d_] := If[r < k, (k - r)*r - (d - 1), If[k < r && r < d, (d - r)*(r - k) - (d - 1), If[k == r && r == d, d - 1, 0]]] uhat[n_, m_, h_] := (dx = Divisors[n]; dmin = n; For[i = 1, i ≤ Length[dx], i++, d = dx[[i]]; k = m - d*Ceiling[m/d] + d; r = h - d*Ceiling[h/d] + d; If[h ≤ Min[k, d - 1], dmin = Min[dmin, n, (h*Ceiling[m/d] - h + 1)*d, h*m - h*h + 1], dmin = Min[dmin, n, h*m - h*h + 1 - delta[r, k, d]]]]; dmin) Table[uhat[n, 1, 8], {n, 1, 70}]
%Y A291502 Cf. A289435, A289436, A289437, A289438, A289439, A289440, A289441.
%K A291502 sign
%O A291502 1,1
%A A291502 _Robert Price_, Aug 24 2017