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.

A247703 Number T(n,k) of tilings of a 5 X n rectangle with pentominoes of any shape and exactly k pentominoes of shape I; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 4, 0, 1, 47, 8, 0, 1, 394, 94, 12, 0, 1, 2082, 1608, 282, 32, 0, 2, 15113, 8812, 3452, 512, 58, 0, 3, 111664, 73863, 22310, 5962, 790, 96, 0, 4, 789930, 631700, 218608, 45762, 9374, 1260, 142, 0, 5, 5388729, 5157928, 2067811, 491868, 81720, 15272, 1824, 196, 0, 6
Offset: 0

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Author

Alois P. Heinz, Sep 22 2014

Keywords

Comments

Sum_{k>0} k * T(n,k) = A247736(n).

Examples

			T(5,5) = 2:
._._._._._.   ._________.
| | | | | |   |_________|
| | | | | |   |_________|
| | | | | |   |_________|
| | | | | |   |_________|
|_|_|_|_|_|   |_________| .
Triangle T(n,k) begins:
00 :      1;
01 :      0,      1;
02 :      4,      0,      1;
03 :     47,      8,      0,     1;
04 :    394,     94,     12,     0,    1;
05 :   2082,   1608,    282,    32,    0,    2;
06 :  15113,   8812,   3452,   512,   58,    0,   3;
07 : 111664,  73863,  22310,  5962,  790,   96,   0,  4;
08 : 789930, 631700, 218608, 45762, 9374, 1260, 142,  0,  5;
		

Crossrefs

Row sums give A174249 or A233427(n,5).
Column k=0 gives A247767.
Main diagonal gives A003520.
Cf. A247736.