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.

A336203 Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where T(n,k) = Sum_{j=0..n} 2^j * binomial(n,j)^k.

Original entry on oeis.org

1, 1, 3, 1, 3, 7, 1, 3, 9, 15, 1, 3, 13, 27, 31, 1, 3, 21, 63, 81, 63, 1, 3, 37, 171, 321, 243, 127, 1, 3, 69, 495, 1521, 1683, 729, 255, 1, 3, 133, 1467, 7761, 14283, 8989, 2187, 511, 1, 3, 261, 4383, 41361, 131283, 138909, 48639, 6561, 1023, 1, 3, 517, 13131, 227601, 1256283, 2336629, 1385163, 265729, 19683, 2047
Offset: 0

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Author

Seiichi Manyama, Jul 11 2020

Keywords

Comments

Column k is the diagonal of the rational function 1 / (Product_{j=1..k} (1-x_j) - 2 * Product_{j=1..k} x_j) for k>0.

Examples

			Square array begins:
   1,   1,    1,     1,      1,       1, ...
   3,   3,    3,     3,      3,       3, ...
   7,   9,   13,    21,     37,      69, ...
  15,  27,   63,   171,    495,    1467, ...
  31,  81,  321,  1521,   7761,   41361, ...
  63, 243, 1683, 14283, 131283, 1256283, ...
		

Crossrefs

Columns k=0-4 give: A000225(n+1), A000244, A001850, A206178, A216696.
Main diagonal gives A336204.
Cf. A309010.

Programs

  • Mathematica
    T[n_, k_] := Sum[2^j * Binomial[n, j]^k, {j, 0, n}]; Table[T[k, n-k], {n, 0, 10}, {k, 0, n}] // Flatten (* Amiram Eldar, May 01 2021 *)