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.

A185738 Rectangular array T(n,k) = 2^n + k - 2, by antidiagonals.

Original entry on oeis.org

1, 2, 3, 3, 4, 7, 4, 5, 8, 15, 5, 6, 9, 16, 31, 6, 7, 10, 17, 32, 63, 7, 8, 11, 18, 33, 64, 127, 8, 9, 12, 19, 34, 65, 128, 255, 9, 10, 13, 20, 35, 66, 129, 256, 511, 10, 11, 14, 21, 36, 67, 130, 257, 512, 1023, 11, 12, 15, 22, 37, 68, 131, 258, 513, 1024, 2047, 12, 13, 16, 23, 38, 69, 132, 259, 514, 1025, 2048, 4095, 13, 14, 17, 24, 39, 70, 133, 260, 515, 1026, 2049, 4096, 8191, 14, 15, 18, 25, 40, 71, 134, 261, 516, 1027, 2050, 4097, 8192, 16383
Offset: 1

Views

Author

Clark Kimberling, Feb 02 2011

Keywords

Comments

This array fits in a chain: ...->(weight array)->A185738->(accumulation array->...
See the Mathematica code and A144112.

Examples

			Northwest corner:
1....2....3....4....5
3....4....5....6....7
7....8....9....10...11
15...16...17...18...19
31...32...33...34...35
		

Crossrefs

Programs

  • Mathematica
    (* This program prints the array T=A185738, the accumulation array A185739 of T, and the weight array A185740 of T. *)
    f[n_,0]:=0;f[0,k_]:=0;
    f[n_,k_]:=2^n+k-2;
    TableForm[Table[f[n,k],{n,1,10},{k,1,15}]]  (* Array A185738 *)
    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 accumulation array *)
    TableForm[Table[s[n,k],{n,1,10},{k,1,15}]]  (* Array A185739 *)
    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}]] (* Array A185740 *)
    Table[w[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten

Formula

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

A185740 Weight array of A185738, by antidiagonals.

Original entry on oeis.org

1, 1, 2, 1, 0, 4, 1, 0, 0, 8, 1, 0, 0, 0, 16, 1, 0, 0, 0, 0, 32, 1, 0, 0, 0, 0, 0, 64, 1, 0, 0, 0, 0, 0, 0, 128, 1, 0, 0, 0, 0, 0, 0, 0, 256, 1, 0, 0, 0, 0, 0, 0, 0, 0, 512, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1024, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2048, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4096, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8192
Offset: 1

Views

Author

Clark Kimberling, Feb 02 2011

Keywords

Comments

This array is a member of a chain. See A185738. A185740 exemplifies the sort of very simple array whose successive accumulation arrays are interesting. The first two accumulation arrays of A185740 are A185738 and A185739.

Examples

			Northwest corner:
1...1...1...1...1...1...1
2...0...0...0...0...0...0
4...0...0...0...0...0...0
8...0...0...0...0...0...0
		

Crossrefs

Cf. A185738.

Programs

  • Mathematica
    (See A185738.)
    f[n_, k_] := 0; f[n_, 1] := 2^(n - 1); f[1, k_] := 1;
    TableForm[Table[f[n, k], {n, 1, 10}, {k, 1, 10}]] (*Array A185740*)
    Table[f[n - k + 1, k], {n, 50}, {k, n, 1, -1}] // Flatten (* G. C. Greubel, Jul 12 2017 *)

Formula

Column 1: 2^n. Row 1: 1,1,1,1,1,1,1,1,1,1,1,... All other terms: 0.
Showing 1-2 of 2 results.