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 A035661 #18 Aug 16 2020 20:50:30
%S A035661 0,0,0,0,0,0,1,1,1,1,1,1,2,4,4,4,4,4,5,7,10,11,11,11,12,14,18,23,25,
%T A035661 26,27,29,33,40,47,52,55,58,62,70,81,93,102,109,115,124,137,155,173,
%U A035661 190,203,216,232,255,283,313,340,365,388,417,454,499,544,590,631,674
%N A035661 Number of partitions of n into parts 7k+1 and 7k+6 with at least one part of each type.
%H A035661 Robert Price, <a href="/A035661/b035661.txt">Table of n, a(n) for n = 1..1000</a>
%F A035661 G.f. : (-1 + 1/Product_{k>=0} (1 - x^(7 k + 6)))*(-1 + 1/Product_{k>=0} (1 - x^(7 k + 1))). - _Robert Price_, Aug 14 2020
%t A035661 nmax = 66; s1 = Range[0, nmax/7]*7 + 1; s2 = Range[0, nmax/7]*7 + 6;
%t A035661 Table[Count[IntegerPartitions[n, All, s1~Join~s2],
%t A035661 x_ /; ContainsAny[x, s1 ] && ContainsAny[x, s2 ]], {n, 1, nmax}] (* _Robert Price_, Aug 14 2020 *)
%t A035661 nmax = 66; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(7 k + 1)), {k, 0, nmax}])*(-1 + 1/Product[(1 - x^(7 k + 6)), {k, 0, nmax}]), {x, 0, nmax}], x] (* _Robert Price_, Aug 14 2020 *)
%Y A035661 Cf. A035441-A035468, A035618-A035660, A035662-A035699.
%K A035661 nonn
%O A035661 1,13
%A A035661 _Olivier Gérard_