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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.

A104746 Array T(n,k) read by antidiagonals: T(1,k) = 2^k-1 and recursively T(n,k) = T(n-1,k) + A000337(k-1), n,k >= 1.

Original entry on oeis.org

1, 1, 3, 1, 4, 7, 1, 5, 12, 15, 1, 6, 17, 32, 31, 1, 7, 22, 49, 80, 63, 1, 8, 27, 66, 129, 192, 127, 1, 9, 32, 83, 178, 321, 448, 255, 1, 10, 37, 100, 227, 450, 769, 1024, 511, 1, 11, 42, 117, 276, 579, 1090, 1793, 2304, 1023, 1, 12, 47, 134, 325, 708, 1411, 2562, 4097, 5120, 2047, 1, 13, 52, 151, 374, 837, 1732, 3331, 5890, 9217, 11264, 4095
Offset: 1

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Author

Gary W. Adamson, Mar 23 2005

Keywords

Comments

Generally, row n of the array is the binomial transform for 0, 1, n, 2n-1, 3n-2, 4n-3, ...

Examples

			To the first row, add the terms 0, 1, 5, 17, 49, 129, ... as indicated:
  1, 3,  7, 15, 31,  63, ...
  0, 1,  5, 17, 49, 129, ... (getting row 2 of the array:
  1, 4, 12, 32, 80, 192, ... (= A001787, binomial transform for 1,2,3, ...)
Repeat the operation, getting the following array T(n,k):
  1, 3,  7, 15,  31,  63, ...
  1, 4, 12, 32,  80, 192, ...
  1, 5, 17, 49, 129, 321, ...
  1, 6, 22, 66, 178, 450, ...
		

Crossrefs

Cf. A104747 (antidiagonal sums), A001787, A000337, A027992, A059823.

Programs

  • Maple
    A000337 := proc(n)
            1+(n-1)*2^n ;
    end proc:
    A104746 := proc(n,k)
            option remember;
            if n=  1 then
                    2^k-1 ;
            else
                    procname(n-1,k)+A000337(k-1) ;
            end if;
    end proc:
    for d from 1 to 12 do
            for k from 1 to d do
                    n := d-k+1 ;
                    printf("%d,",A104746(n,k)) ;
            end do:
    end do; # R. J. Mathar, Oct 30 2011
  • Mathematica
    A000337[n_] := (n - 1)*2^n + 1;
    T[1, k_] := 2^k - 1;
    T[n_, k_] := T[n, k] = T[n - 1, k] + A000337[k - 1];
    Table[T[n - k + 1, k], {n, 1, 12}, {k, 1, n}] // Flatten (* Jean-François Alcover, Mar 30 2024 *)

Formula

T(2,k) = A001787(k), binomial transform of 0, 1, 2, 3, 4, 5, 6, ...
T(3,k) = A000337(k), binomial transform of 0, 1, 3, 5, 7, 9, 11, ...
T(4,k) = A027992(k-1), binomial transform of 0, 1, 4, 7, 10, 13, 16, 19, 22, 25, ...
T(5,k) = binomial transform of 0, 1, 5, 9, 13, 17, 21, 25, 29, ...

Extensions

Terms corrected by R. J. Mathar, Oct 30 2011