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 A365007 #17 Oct 25 2023 18:21:39
%S A365007 1,2,7,6,16,17,29,22,52,42,67,57,92,79,142,86,154,143,191,146,266,189,
%T A365007 277,217,341,262,430,279,436,402,497,342,634,444,674,507,704,553,878,
%U A365007 562,862,766,947,677,1222,807,1129,857,1254,992,1486,942,1432,1250,1622,1079
%N A365007 a(n) = Sum_{d|n} (-1)^(n/d-1) * binomial(d+1,2).
%H A365007 Michael De Vlieger, <a href="/A365007/b365007.txt">Table of n, a(n) for n = 1..10000</a>
%F A365007 G.f.: -Sum_{k>=1} (-x)^k/(1-x^k)^3 = Sum_{k>=1} binomial(k+1,2) * x^k/(1+x^k).
%t A365007 Table[DivisorSum[n, (-1)^(n/# - 1)*Binomial[# + 1, 2] &], {n, 56}] (* _Michael De Vlieger_, Oct 25 2023 *)
%o A365007 (PARI) a(n) = sumdiv(n, d, (-1)^(n/d-1)*binomial(d+1, 2));
%Y A365007 Partial sums give A366395.
%Y A365007 Cf. A000593, A366813, A366814.
%Y A365007 Cf. A007437.
%K A365007 nonn,look
%O A365007 1,2
%A A365007 _Seiichi Manyama_, Oct 24 2023