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A210980 Total area of the shadows of the three views of the shell model of partitions, version "Tree", with n shells. 6
0, 3, 10, 21, 42, 69, 123, 189, 304, 458, 693, 998, 1474, 2067, 2927, 4056, 5613, 7595, 10335, 13782, 18411, 24276, 31944, 41583, 54152, 69762, 89758, 114668, 146181, 185083, 234051, 294126, 368992, 460669, 573906, 711865, 881506, 1087023, 1338043 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Each part is represented by a cuboid 1 X 1 X L where L is the size of the part.

LINKS

Table of n, a(n) for n=0..38.

FORMULA

a(n) = A066186(n) + A194804(n) + A194805(n), n >= 1.

EXAMPLE

For n = 7 the shadows of the three views of the shell model of partitions version "tree" with seven shells looks like this:

.                                        |  Partitions

.    A194805(7) = 25    A066186(7) = 105 |  of 7

.                                        |

.                   1    * * * * * * 1   |  7

.                 2      * * * 1 * * 2   |  4+3

.               2        * * * * 1 * 2   |  5+2

.             3          * * 1 * 2 * 3   |  3+2+2

.   1       2            * * * * * 1 2   |  6+1

.     2     3            * * 1 * * 2 3   |  3+3+1

.       2   3            * * * 1 * 2 3   |  4+2+1

.         3 4            * 1 * 2 * 3 4   |  2+2+2+1

.           3   1        * * * * 1 2 3   |  5+1+1

.           4 2          * * 1 * 2 3 4   |  3+2+1+1

.       1   4            * * * 1 2 3 4   |  4+1+1+1

.         2 5            * 1 * 2 3 4 5   |  2+2+1+1+1

.           5 1          * * 1 2 3 4 5   |  3+1+1+1+1

.         1 6            * 1 2 3 4 5 6   |  2+1+1+1+1+1

.           7            1 2 3 4 5 6 7   |  1+1+1+1+1+1+1

.   ----------------------------------   |

.                                        |

.   * * * * 1 * * * *                    |

.   * * * 1 2 * * * *                    |

.   * 1 * * 2 1 * * *                    |

.   * * 1 2 2 * * 1 *                    |

.   * * * * 2 2 1 * *                    |

.   1 2 2 3 2 * * * *                    |

.           2 3 2 2 1                    |

.                                        |

.    A194804(7) = 59                     |

.

Note that, as a variant, in this case each part is labeled with its position in the partition.

The areas of the shadows of the three views are A066186(7) = 105, A194804(7) = 59 and A194805(7) = 25, therefore the total area of the three shadows is 105+59+25 = 189, so a(7) = 189.

CROSSREFS

Other versions: A207380, A210970, A210979, A210990, A210991.

Cf. A000041, A066186, A135010, A138121, A141285, A182703, A194804, A194805, A206437.

Sequence in context: A027917 A038347 A294365 * A207380 A268348 A117495

Adjacent sequences:  A210977 A210978 A210979 * A210981 A210982 A210983

KEYWORD

nonn

AUTHOR

Omar E. Pol, Apr 21 2012

STATUS

approved

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Last modified May 21 03:30 EDT 2019. Contains 323434 sequences. (Running on oeis4.)