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.

A162453 Plane partition triangle, row sums = A000219; derived from the Euler transform of [1, 2, 3, ...].

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 5, 3, 4, 1, 5, 9, 4, 5, 1, 9, 15, 12, 5, 6, 1, 9, 24, 24, 15, 6, 7, 1, 14, 36, 46, 30, 18, 7, 8, 1, 14, 58, 70, 65, 36, 21, 8, 9, 1, 20, 76, 130, 110, 78, 42, 24, 9, 10, 1, 20, 111, 196, 200, 144, 91, 48, 27, 10, 11, 1, 27, 150, 314, 335, 273, 168, 104, 54, 30
Offset: 1

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Author

Gary W. Adamson, Jul 03 2009

Keywords

Comments

Row sums = A000219, number of planar partitions of n starting with offset 1.

Examples

			First few rows of the array:
  1,  1,  1,  1,  1,  1, ...; = a
  1,  1,  3,  3,  6,  6, ...; = a*b
  1,  1,  3,  6,  9, 15, ...; = a*b*c
  1,  1,  3,  6, 13, 19, ...; = a*b*c*d
  1,  1,  3,  6, 13, 24, ...; = a*b*c*d*e
  ...
then taking finite differences from the top and discarding the first "1" we obtain:
  1;
  1,  2;
  1,  2,   3;
  1,  5,   3,   4;
  1,  5,   9,   4,   5;
  1,  9,  15,  12,   5,   6;
  1,  9,  24,  24,  15,   6,   7;
  1, 14,  36,  46,  30,  18,   7,   8;
  1, 14,  58,  70,  65,  36,  21,   8,  9;
  1, 20,  76, 130, 110,  78,  42,  24,  9, 10;
  1, 20, 111, 196, 200, 144,  91,  48, 27, 10, 11;
  1, 27, 150, 314, 335, 273, 168, 104, 54, 30, 11, 12;
  ...
		

Crossrefs

Cf. A000219.

Formula

Construct an array with rows = a, a*b, a*b*c, ...; where a = [1, 1, 1, ...], b = [1, 0, 2, 0, 3, ...], c = [1, 0, 0, 3, 0, 0, 6, ...], d = [1, 0, 0, 0, 4, 0, 0, 0, 10, 0, 0, 0, 20, ...] etc., where rows converge to A000219: (1, 1, 3, 6, 13, 24, ...). The triangle = finite differences of column terms starting from the top.