cp's OEIS Frontend

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.

Showing 1-2 of 2 results.

A185910 Array: T(n,k) = n^2 + k - 1, by antidiagonals.

Original entry on oeis.org

1, 2, 4, 3, 5, 9, 4, 6, 10, 16, 5, 7, 11, 17, 25, 6, 8, 12, 18, 26, 36, 7, 9, 13, 19, 27, 37, 49, 8, 10, 14, 20, 28, 38, 50, 64, 9, 11, 15, 21, 29, 39, 51, 65, 81, 10, 12, 16, 22, 30, 40, 52, 66, 82, 100, 11, 13, 17, 23, 31, 41, 53, 67, 83, 101, 121, 12, 14, 18, 24, 32, 42, 54, 68, 84, 102, 122, 144, 13, 15, 19, 25, 33, 43, 55, 69, 85, 103, 123, 145, 169, 14, 16, 20, 26, 34, 44, 56, 70, 86, 104, 124, 146, 170, 196
Offset: 1

Views

Author

Clark Kimberling, Feb 06 2011

Keywords

Comments

A member of the accumulation chain ... < A185911 < A185910 < A185912 < A185913 < ... (See A144112 for definitions of weight array and accumulation array.)

Examples

			Northwest corner:
   1,  2,  3,  4,  5
   4,  5,  6,  7,  8
   9, 10, 11, 12, 13
  16, 17, 18, 19, 20
		

Crossrefs

Programs

  • Mathematica
    (* This program generates the array A185910, its accumulation array A185812, and its weight array A185911. *)
    f[n_,0]:=0;f[0,k_]:=0;
    f[n_,k_]:=n^2+k-1;
    TableForm[Table[f[n,k],{n,1,10},{k,1,15}]] (* A185910 *)
    Table[f[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten
    s[n_,k_]:=Sum[f[i,j],{i,1,n},{j,1,k}]; (* accumulation array of {f(n,k)} *)
    FullSimplify[s[n,k]]  (* formula for A185812 *)
    TableForm[Table[s[n,k],{n,1,10},{k,1,15}]]
    Table[s[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten
    w[m_,n_]:=f[m,n]+f[m-1,n-1]-f[m,n-1]-f[m-1,n]/;Or[m>0,n>0];
    TableForm[Table[w[n,k],{n,1,10},{k,1,15}]] (* A185911 *)
    Table[w[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten

Formula

T(n,k) = n^2 + k - 1, k >= 1, n >= 1.

A185912 Accumulation array of A185910; by antidiagonals.

Original entry on oeis.org

1, 3, 5, 6, 12, 14, 10, 21, 31, 30, 15, 32, 51, 64, 55, 21, 45, 74, 102, 115, 91, 28, 60, 100, 144, 180, 188, 140, 36, 77, 129, 190, 250, 291, 287, 204, 45, 96, 161, 240, 325, 400, 441, 416, 285, 55, 117, 196, 294, 405, 515, 602, 636, 579, 385, 66, 140, 234, 352, 490, 636, 770, 864, 882, 780, 506, 78, 165, 275, 414, 580, 763, 945, 1100, 1194, 1185, 1023, 650, 91, 192, 319, 480, 675, 896, 1127, 1344, 1515, 1600, 1551, 1312, 819, 105
Offset: 1

Views

Author

Clark Kimberling, Feb 06 2011

Keywords

Comments

A member of the accumulation chain ... < A185910 < A185911 < A185912 < A185913 < ...
(See A144112 for definitions of weight array and accumulation array.)

Examples

			Northwest corner:
   1,   3,   6,  10,  15
   5,  12,  21,  32,  45
  14,  31,  51,  74, 100
  30,  64, 102, 144, 190
		

Crossrefs

Row 1 to 2: A000217, A028347.
Column 1 to 3: A000330, A037237, 3*A145066.

Programs

  • Mathematica
    f[n_, 0] := 0; f[0, k_] := 0;
    f[n_, k_] := n^2 + k - 1;
    s[n_, k_] := Sum[f[i, j], {i, 1, n}, {j, 1, k}];(*accumulation array of {f(n,k)}*)
    FullSimplify[s[n, k]]  (*formula for A185812*)
    Table[s[n - k + 1, k], {n, 10}, {k, n, 1, -1}] // Flatten
    T[n_, k_] := (k*n/6)*(2*n^2 + 3*n + 3*k - 2) ; Table[T[n - k + 1, k], {n, 10}, {k, n, 1, -1}] // Flatten (* G. C. Greubel, Jul 22 2017 *)

Formula

T(n,k) = (k*n/6)*(2*n^2 + 3*n + 3*k - 2), k >= 1, n >= 1.
Showing 1-2 of 2 results.