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.

A163311 Triangle read by rows in which the diagonals give the infinite set of Toothpick sequences.

Original entry on oeis.org

1, 1, 2, 1, 3, 4, 1, 4, 7, 5, 1, 5, 10, 11, 7, 1, 6, 13, 19, 15, 10, 1, 7, 16, 29, 25, 23, 13, 1, 8, 19, 41, 37, 40, 35, 14, 1, 9, 22, 55, 51, 61, 67, 43, 16, 1, 10, 25, 71, 67, 86, 109, 94, 47, 19, 1, 11, 28, 89, 85, 115, 161, 173, 100, 55, 22, 1, 12, 31, 109, 105, 148, 223, 286, 181
Offset: 1

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Author

Gary W. Adamson, Jul 24 2009

Keywords

Comments

Apart from the second diagonal (which gives the toothpick sequence A139250), the rest of the diagonals cannot be represented with toothpick structures. - Omar E. Pol, Dec 14 2016

Examples

			Triangle begins:
1;
1, 2;
1, 3,  4;
1, 4,  7,  5;
1, 5,  10, 11,  7;
1, 6,  13, 19,  15,  10;
1, 7,  16, 29,  25,  23,  13;
1, 8,  19, 41,  37,  40,  35,  14;
1, 9,  22, 55   51,  61,  67,  43,  16;
1, 10, 25, 71,  67,  86,  109, 94,  47,  19;
1, 11, 28, 89,  85,  115, 161, 173, 100, 55,  22;
1, 12, 31, 109, 105, 148, 223, 286, 181, 115, 67,  25;
1, 13, 34, 131, 127, 185, 295, 439, 296, 205, 142, 79,  30;
1, 14, 37, 155, 151, 226, 377, 638, 451, 331, 253, 175, 95, 36;
...
		

Crossrefs

Row sums = A163312: (1, 3, 8, 17, 34, 64,...).
Right border = A163267, toothpick sequence for N=1.
Next diagonal going to the left = A139250, toothpick sequence for N=2.
Then 1, 4, 10, 19,... = A162958, toothpick sequence for N=3.

Formula

See A162958 for rules governing the generation of N-th Toothpick sequences. By way of example, (N+2), A139250. The generator is A160552, which uses the multiplier "2". Then A160552 convolved with (1, 2, 2, 2,...) = A139250 the Toothpick sequence for N=2. Similarly, we create an array for Toothpick sequences N=1, 2, 3,...etc = A163267, A139250, A162958,...; then take the antidiagonals, creating triangle A163311.