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 A366723 #28 Oct 24 2023 11:46:38
%S A366723 1,5,21,50,121,236,447,736,1247,1896,2898,4151,5972,8146,11292,14797,
%T A366723 19643,25248,32564,40663,51515,63168,78119,94452,114998,136933,164849,
%U A366723 193753,229714,268334,314711,362824,422746,483950,558046,635070,726461,820420,934186,1048245
%N A366723 a(n) = Sum_{k=1..n} (-1)^(k-1) * binomial(floor(n/k)+4,5).
%F A366723 a(n) = Sum_{k=1..n} binomial(k+3,4) * (floor(n/k) mod 2).
%F A366723 G.f.: -1/(1-x) * Sum_{k>=1} (-x)^k/(1-x^k)^5 = 1/(1-x) * Sum_{k>=1} binomial(k+3,4) * x^k/(1+x^k).
%o A366723 (PARI) a(n) = sum(k=1, n, (-1)^(k-1)*binomial(n\k+4, 5));
%Y A366723 Partial sums of A366814.
%Y A366723 Cf. A078471, A366395, A366659.
%Y A366723 Cf. A365439.
%K A366723 nonn
%O A366723 1,2
%A A366723 _Seiichi Manyama_, Oct 24 2023