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.

A134836 Antidiagonals of the array: A007318 * A002260(transposed).

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 5, 3, 1, 1, 7, 8, 3, 1, 1, 9, 16, 8, 3, 1, 1, 11, 27, 20, 8, 3, 1, 1, 13, 41, 43, 20, 8, 3, 1, 1, 15, 58, 81, 48, 20, 8, 3, 1, 1, 17, 78, 138, 106, 48, 20, 8, 3, 1, 1, 19, 101, 218, 213, 112, 48, 20, 8, 3, 1
Offset: 1

Views

Author

Gary W. Adamson, Nov 12 2007

Keywords

Comments

Antidiagonals tend to A001792 starting from the right: (1, 3, 8, 20, 48, 112, ...).

Examples

			First few rows of the array:
  1,  1,  1,  1,   1,   1, ...;
  1,  3,  3,  3,   3,   3, ...;
  1,  5,  8,  8,   8,   8, ...;
  1,  7, 16, 20,  20,  20, ...;
  1,  9, 27, 43,  48,  48, ...;
  1, 11, 41, 81, 106, 112, ...;
  ...
First few rows of the triangle:
  1;
  1,  1;
  1,  3,  1;
  1,  5,  3,  1;
  1,  7,  8,  3,  1;
  1,  9, 16,  8,  3,  1;
  1, 11, 27, 20,  8,  3,  1;
  1, 13, 41, 43, 20,  8,  3,  1;
  ...
		

Crossrefs

Cf. A002260, A001792, A116445 (array transposed), A001629 (antidiagonal sums).

Programs

  • Maple
    A002260 := proc(n,k)
        if n <= k then
            n+1;
        else
            0 ;
        end if;
    end proc:
    A007318 := proc(n,k)
        if k <= n then
            binomial(n,k) ;
        else
            0
        end if;
    end proc:
    A134836 := proc(n,k)
        add( A007318(n,i)*A002260(i,k),i=0..k) ;
    end proc:
    seq(seq(A134836(d-k,k),k=0..d),d=0..12) ; # R. J. Mathar, Aug 17 2022

Formula

Antidiagonals of the array: A007318 * A002260(transform), where A002260 = (1; 1,2; 1,2,3; ...).

Extensions

One term corrected by R. J. Mathar, Aug 17 2022

A139488 Binomial transform of [1, 2, 3, 4, 0, 0, 0, ...].

Original entry on oeis.org

1, 3, 8, 20, 43, 81, 138, 218, 325, 463, 636, 848, 1103, 1405, 1758, 2166, 2633, 3163, 3760, 4428, 5171, 5993, 6898, 7890, 8973, 10151, 11428, 12808, 14295, 15893, 17606, 19438, 21393, 23475, 25688, 28036, 30523, 33153, 35930, 38858, 41941, 45183
Offset: 0

Views

Author

Gary W. Adamson, Apr 23 2008

Keywords

Examples

			a(5) = 43 = (1, 4, 6, 4, 1) dot (1, 2, 3, 4, 0) = (1 + 8, + 18 + 16 + 0).
		

Crossrefs

Programs

  • Maple
    a:=proc(n) options operator, arrow: (2/3)*n^3-(1/2)*n^2+(11/6)*n+1 end proc: seq(a(n),n=0..35); # Emeric Deutsch, Apr 30 2008
  • Mathematica
    f[n_] := Plus @@ (Table[ Binomial[n - 1, i], {i, 0, n - 1}] PadRight[{1, 2, 3, 4}, n]); Array[f, 43] (* Robert G. Wilson v, Apr 24 2008 *)

Formula

Equals A007318 * [1, 2, 3, 4, 0, 0, 0, ...].
a(n) = (4n^3 - 3n^2 + 11n + 6)/6. - Emeric Deutsch, Apr 30 2008
G.f.: (1 - x + 2*x^2 + 2*x^3)/(1-x)^4. - Colin Barker, Feb 01 2012

Extensions

More terms from Robert G. Wilson v and Emeric Deutsch, Apr 24 2008
Showing 1-2 of 2 results.