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 A339279 #4 Nov 29 2020 22:48:26
%S A339279 1,1,2,3,4,5,7,8,10,13,15,18,22,25,29,34,38,43,50,55,62,70,77,85,95,
%T A339279 103,113,126,136,149,164,177,192,210,225,243,265,283,305,330,352,377,
%U A339279 406,431,460,494,523,557,595,629,667,710,748,791,841,884,934,989,1039,1094,1156
%N A339279 Number of partitions of 3*n into powers of 3 where every part appears at least 2 times.
%H A339279 <a href="/index/Par#part">Index entries for sequences related to partitions</a>
%F A339279 G.f.: (1/(1 - x^2)) * Product_{k>=0} 1/(1 - x^(3^k)).
%F A339279 G.f.: (1/(1 - x)) * Product_{k>=0} (1 + x^(2*3^k)/(1 - x^(3^k))).
%F A339279 a(n) = [x^(3*n)] Product_{k>=0} (1 + x^(2*3^k)/(1 - x^(3^k))).
%F A339279 a(n) = Sum_{k=0..n} (-1)^(n-k) * A005704(k).
%e A339279 a(3) = 3 because we have [3, 3, 3], [3, 3, 1, 1, 1] and [1, 1, 1, 1, 1, 1, 1, 1, 1].
%t A339279 nmax = 60; CoefficientList[Series[(1/(1 - x^2)) Product[1/(1 - x^(3^k)), {k, 0, Floor[Log[3, nmax]] + 1}], {x, 0, nmax}], x]
%t A339279 A005704[0] = 1; A005704[n_] := A005704[n] = A005704[n - 1] + A005704[Floor[n/3]]; a[n_] := Sum[(-1)^(n - k) A005704[k], {k, 0, n}]; Table[a[n], {n, 0, 60}]
%Y A339279 Cf. A000244, A005704, A007690, A062051, A339277.
%K A339279 nonn
%O A339279 0,3
%A A339279 _Ilya Gutkovskiy_, Nov 29 2020