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 A292741 #29 Oct 26 2018 17:05:08 %S A292741 1,1,0,1,1,1,1,2,2,1,1,3,5,3,2,1,4,10,11,5,2,1,5,17,31,24,7,4,1,6,26, %T A292741 69,95,50,11,4,1,7,37,131,278,287,104,15,7,1,8,50,223,657,1114,865, %U A292741 212,22,8,1,9,65,351,1340,3287,4460,2599,431,30,12,1,10,82,521,2459,8042,16439,17844,7804,870,42,14 %N A292741 Number A(n,k) of partitions of n with k sorts of part 1; square array A(n,k), n>=0, k>=0, read by antidiagonals. %H A292741 Alois P. Heinz, <a href="/A292741/b292741.txt">Antidiagonals n = 0..140, flattened</a> %F A292741 G.f. of column k: 1/(1-k*x) * 1/Product_{j>=2} (1-x^j). %F A292741 A(n,k) = Sum_{j=0..n} A002865(j) * k^(n-j). %e A292741 A(1,3) = 3: 1a, 1b, 1c. %e A292741 A(2,3) = 10: 2, 1a1a, 1a1b, 1a1c, 1b1a, 1b1b, 1b1c, 1c1a, 1c1b, 1c1c. %e A292741 A(3,2) = 11: 3, 21a, 21b, 1a1a1a, 1a1a1b, 1a1b1a, 1a1b1b, 1b1a1a, 1b1a1b, 1b1b1a, 1b1b1b. %e A292741 Square array A(n,k) begins: %e A292741 1, 1, 1, 1, 1, 1, 1, 1, ... %e A292741 0, 1, 2, 3, 4, 5, 6, 7, ... %e A292741 1, 2, 5, 10, 17, 26, 37, 50, ... %e A292741 1, 3, 11, 31, 69, 131, 223, 351, ... %e A292741 2, 5, 24, 95, 278, 657, 1340, 2459, ... %e A292741 2, 7, 50, 287, 1114, 3287, 8042, 17215, ... %e A292741 4, 11, 104, 865, 4460, 16439, 48256, 120509, ... %e A292741 4, 15, 212, 2599, 17844, 82199, 289540, 843567, ... %p A292741 b:= proc(n, i, k) option remember; `if`(n=0 or i<2, k^n, %p A292741 add(b(n-i*j, i-1, k), j=0..iquo(n, i))) %p A292741 end: %p A292741 A:= (n, k)-> b(n$2, k): %p A292741 seq(seq(A(n, d-n), n=0..d), d=0..14); %t A292741 b[0, _, _] = 1; b[n_, i_, k_] := b[n, i, k] = If[i < 2, k^n, Sum[b[n - i*j, i - 1, k], {j, 0, Quotient[n, i]}]]; %t A292741 A[n_, k_] := b[n, n, k]; %t A292741 Table[A[n, d - n], {d, 0, 14}, {n, 0, d}] // Flatten (* _Jean-François Alcover_, May 19 2018, translated from Maple *) %Y A292741 Columns k=0-2 give: A002865, A000041, A090764. %Y A292741 Rows n=0-2 give: A000012, A001477, A002522, A071568. %Y A292741 Main diagonal gives A292462. %Y A292741 Cf. A003992, A004248, A009998, A051129, A292508, A292622, A292745. %K A292741 nonn,tabl %O A292741 0,8 %A A292741 _Alois P. Heinz_, Sep 22 2017