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 A282499 #10 Feb 16 2025 08:33:41
%S A282499 0,0,0,1,0,0,3,0,0,3,3,3,1,6,6,0,3,6,9,3,3,12,3,0,4,9,9,4,6,9,6,0,9,
%T A282499 12,12,9,9,18,9,6,12,18,18,6,21,21,6,6,10,24,9,12,15,18,12,3,18,12,18,
%U A282499 12,18,24,15,9,9,18,24,15,18,24,9,6,18,24,12,13,15,27,6,9,15,19,18,9,24,12,18,0,15,24,27,9,12,24,12,12
%N A282499 Expansion of (Sum_{k = i^j, i>=1, j>=2, excluding duplicates} x^k)^3.
%C A282499 Number of ways to write n as an ordered sum of 3 perfect powers (A001597).
%H A282499 Ilya Gutkovskiy, <a href="/A282499/a282499.pdf">Extended graphical example</a>
%H A282499 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PerfectPower.html">Perfect Powers</a>
%F A282499 G.f.: (Sum_{k = i^j, i>=1, j>=2, excluding duplicates} x^k)^3.
%e A282499 a(14) = 6 because we have [9, 4, 1], [9, 1, 4], [4, 9, 1], [4, 1, 9], [1, 9, 4] and [1, 4, 9].
%t A282499 nmax = 95; CoefficientList[Series[(x + Sum[Boole[GCD @@ FactorInteger[k][[All, 2]] > 1] x^k, {k, 2, nmax}])^3, {x, 0, nmax}], x]
%Y A282499 Cf. A001597, A078635, A113505.
%K A282499 nonn
%O A282499 0,7
%A A282499 _Ilya Gutkovskiy_, Feb 16 2017