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 1-3 of 3 results.

A185878 Accumulation array of A185877, by antidiagonals.

Original entry on oeis.org

1, 4, 2, 11, 10, 3, 24, 28, 18, 4, 45, 60, 51, 28, 5, 76, 110, 108, 80, 40, 6, 119, 182, 195, 168, 115, 54, 7, 176, 280, 318, 300, 240, 156, 70, 8, 249, 408, 483, 484, 425, 324, 203, 88, 9, 340, 570, 696, 728, 680, 570, 420, 256, 108, 10, 451, 770, 963, 1040, 1015, 906, 735, 528, 315, 130, 11, 584, 1012, 1290, 1428, 1440, 1344, 1162, 920, 648, 380, 154, 12
Offset: 1

Views

Author

Clark Kimberling, Feb 05 2011

Keywords

Comments

A member of the accumulation chain ... < A185879 < A185877 < A185878 < A185880 < ...
See A144112 for the definition of accumulation array.

Examples

			Northwest corner:
  1,  4, 11,  24,  45, ...
  2, 10, 28,  60, 110, ...
  3, 18, 51, 108, 195, ...
  4, 28, 80, 168, 300, ...
  ...
		

Crossrefs

Row 1 to 3: A006527, A006331, A064043.
Column 1 to 5: A000027, A028552, A140677, 12*A000096, 5*A130861.

Programs

  • Mathematica
    f[n_, k_] := k*n*(2*k^2 - 3*k + 3*k*n - 3*n + 7)/6; Table[f[n - k + 1, k], {n,10}, {k, n, 1, -1}] // Flatten (* G. C. Greubel, Jul 21 2017 *)

Formula

T(n,k) = k*n*(2*k^2 -3*k +3*k*n -3*n +7)/6, k>=1, n>=1.

A185879 Weight array of A185877, by antidiagonals.

Original entry on oeis.org

1, 2, 0, 4, 2, 0, 6, 2, 2, 0, 8, 2, 2, 2, 0, 10, 2, 2, 2, 2, 0, 12, 2, 2, 2, 2, 2, 0, 14, 2, 2, 2, 2, 2, 2, 0, 16, 2, 2, 2, 2, 2, 2, 2, 0, 18, 2, 2, 2, 2, 2, 2, 2, 2, 0, 20, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 22, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 24, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 26, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0
Offset: 1

Views

Author

Clark Kimberling, Feb 05 2011

Keywords

Comments

A member of the accumulation chain ...< A185879 < A185877 < A185878 < A185880 <...
See A144112 for the definitions of weight array and accumulation array.

Examples

			Northwest corner:
1...2...4...6...8...10...12...14
0...2...2...2...2...2....2....2
0...2...2...2...2...2....2....2
0...2...2...2...2...2....2....2
0...2...2...2...2...2....2....2
		

Crossrefs

Programs

  • Mathematica
    f[n_, k_] := 2; f[1, k_] := 2*(k - 1); f[n_, 1] := 0; f[1, 1] := 1;
    TableForm[Table[f[n, k], {n, 1, 7}, {k, 1, 7}]] Table[f[n - k + 1, k], {n, 5}, {k, n, 1, -1}] // Flatten (* G. C. Greubel, Jul 21 2017 *)

Formula

T(1,k) = 2*(k-1) for k>=1; T(n,1)=0 for n>1; T(n,k)=2 otherwise.

A185880 Second accumulation array of A185877, by antidiagonals.

Original entry on oeis.org

1, 5, 3, 16, 17, 6, 40, 56, 38, 10, 85, 140, 128, 70, 15, 161, 295, 320, 240, 115, 21, 280, 553, 670, 600, 400, 175, 28, 456, 952, 1246, 1250, 1000, 616, 252, 36, 705, 1536, 2128, 2310, 2075, 1540, 896, 348, 45, 1045, 2355, 3408, 3920, 3815, 3185, 2240, 1248, 465, 55, 1496, 3465, 5190, 6240, 6440, 5831, 4620, 3120, 1680, 605, 66, 2080, 4928, 7590, 9450, 10200, 9800, 8428, 6420, 4200, 2200
Offset: 1

Views

Author

Clark Kimberling, Feb 05 2011

Keywords

Comments

A member of the accumulation chain ... < A185879 < A185877 < A185878 < A185880 < ... See A144112 for the definition of accumulation array.

Examples

			Northwest corner:
   1,    5,   16,   40,   85
   3,   17,   56,  140,  295
   6,   38,  128,  320,  670
  10,   70,  240,  600, 1250
		

Crossrefs

Antidiagonal sums: A037235.
diag (1,5,...): A056108 (4th spoke on hexagonal wheel);
diag (3,11,...): A056106 (2nd spoke on hexagonal wheel);
diag (7,19,...): A003215 (hex numbers);
diag (13,29,...): A144391.

Programs

  • Mathematica
    (* This program generates A185878 first and then generates A185880 as the accumulation array of A185878. *)
    f[n_,k_]:=(k*n/6)(7-3k+2k^2-3n+3kn);
    TableForm[Table[f[n,k],{n,1,10},{k,1,15}]] (* A185878 *)
    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}];
    FullSimplify[s[n,k]]
    TableForm[Table[s[n,k],{n,1,10},{k,1,15}]] (* A185880 *)
    f[n_, k_] := (1/72)*k*(1 + k)*n*(1 + n)*(16 - k + 3 *k^2 + 4 *(-1 + k) *n); Table[f[n - k + 1, k], {n, 10}, {k, n, 1, -1}] // Flatten (* G. C. Greubel, Jul 21 2017 *)

Formula

T(n,k) = C(k,2)*C(n,2)*(3*k^2+4*k*n-k-4*n+16)/18, k>=1, n>=1.
Showing 1-3 of 3 results.