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 A119442 #11 Mar 23 2018 20:52:58 %S A119442 1,2,1,3,2,1,5,7,2,1,7,11,7,2,1,11,26,19,7,2,1,15,40,38,19,7,2,1,22, %T A119442 83,78,54,19,7,2,1,30,120,168,102,54,19,7,2,1,42,223,301,244,134,54, %U A119442 19,7,2,1,56,320,557,471,292,134,54,19,7,2,1,77,566,1035,1000,623,356,134,54 %N A119442 Triangle read by rows: row n lists number of unordered partitions of n into k parts which are partition numbers (members of A000041). %C A119442 A060642 describes the ordered case. %C A119442 Number of twice-partitions of n of length k. A twice-partition of n is a choice of a partition of each part in a partition of n. - _Gus Wiseman_, Mar 23 2018 %F A119442 G.f.: 1/Product_{k>0} (1-y*A000041(k)*x^k). - _Vladeta Jovovic_, May 21 2006 %e A119442 Triangle begins: %e A119442 1 %e A119442 2 1 %e A119442 3 2 1 %e A119442 5 7 2 1 %e A119442 7 11 7 2 1 %e A119442 11 26 19 7 2 1 %e A119442 15 40 38 19 7 2 1 %e A119442 22 83 78 54 19 7 2 1 %e A119442 30 120 168 102 54 19 7 2 1 %e A119442 42 223 301 244 134 54 19 7 2 1 %e A119442 56 320 557 471 292 134 54 19 7 2 1 %e A119442 The T(5,3) = 7 twice-partitions: (3)(1)(1), (21)(1)(1), (111)(1)(1), (2)(2)(1), (2)(11)(1), (11)(2)(1), (11)(11)(1). - _Gus Wiseman_, Mar 23 2018 %t A119442 nn=12; %t A119442 ser=Product[1/(1-PartitionsP[n]x^n y),{n,nn}]; %t A119442 Table[SeriesCoefficient[ser,{x,0,n},{y,0,k}],{n,nn},{k,n}] (* _Gus Wiseman_, Mar 23 2018 *) %Y A119442 Cf. A000041, A001970, A008284, A036036, A048996, A055887, A061260, A063834, A273873, A281145, A289501, A299200, A299201. %K A119442 nonn,tabl %O A119442 0,2 %A A119442 _Alford Arnold_, May 19 2006 %E A119442 More terms and better definition from _Vladeta Jovovic_, May 21 2006