OFFSET
1,2
COMMENTS
EXAMPLE
Triangle begins (rows 1..28):
1;
3;
2, 2;
7, 0;
3, 3;
12, 0, 0;
4, 0, 4;
15, 0, 0;
5, 3, 5;
9, 0, 9, 0;
6, 0, 0, 6;
28, 0, 0, 0;
7, 0, 0, 7;
12, 0, 12, 0;
8, 8, 0, 0, 8;
31, 0, 0, 0, 0;
9, 0, 0, 0, 9;
39, 0, 0, 0, 0;
10, 0, 0, 0, 10;
42, 0, 0, 0, 0;
11, 5, 0, 5, 0, 11;
18, 0, 0, 0, 18, 0;
12, 0, 0, 0, 0, 12;
60, 0, 0, 0, 0, 0;
13, 0, 5, 0, 0, 13;
21, 0, 0, 0 21, 0;
14, 6, 0, 6, 0, 14;
56, 0, 0, 0, 0, 0, 0;
...
Illustration of first 50 terms (rows 1..16 of triangle) in an irregular spiral which can be find in the top view of the pyramid described in A244050:
.
. 12 _ _ _ _ _ _ _ _
. | _ _ _ _ _ _ _|_ _ _ _ _ _ _ 7
. | | |_ _ _ _ _ _ _|
. 0 _| | |
. |_ _|9 _ _ _ _ _ _ |_ _ 0
. 12 _ _| | _ _ _ _ _|_ _ _ _ _ 5 |_ 0
. 0 _ _ _| | 0 _| | |_ _ _ _ _| |
. | _ _ _| 9 _|_ _| |_ _ 3 |_ _ _ 7
. | | 0 _ _| | 12 _ _ _ _ |_ | | |
. | | | _ _| 0 _| _ _ _|_ _ _ 3 |_|_ _ 5 | |
. | | | | 0 _| | |_ _ _| | | | |
. | | | | | _ _| |_ _ 3 | | | |
. | | | | | | 3 _ _ | | | | | |
. | | | | | | | _|_ 1 | | | | | |
. _|_| _|_| _|_| _|_| |_| _|_| _|_| _|_| _
. | | | | | | | | | | | | | | | |
. | | | | | | |_|_ _ _| | | | | | | |
. | | | | | | 2 |_ _|_ _| _| | | | | | |
. | | | | |_|_ 2 |_ _ _| 0 _ _| | | | | |
. | | | | 4 |_ 7 _| _ _|0 | | | |
. | | |_|_ _ 0 |_ _ _ _ | _| _ _ _| | | |
. | | 6 |_ |_ _ _ _|_ _ _ _| | 0 _| _ _|0 | |
. |_|_ _ _ 0 |_ 4 |_ _ _ _ _| _| | _ _ _| |
. 8 | |_ _ 0 | 15| _| | _ _ _|
. |_ | |_ _ _ _ _ _ | _ _| 0 _| | 0
. 8 |_ |_ |_ _ _ _ _ _|_ _ _ _ _ _| | 0 _| _|
. 0 |_ _| 6 |_ _ _ _ _ _ _| _ _| _| 0
. 0 | 28| _ _| 0
. |_ _ _ _ _ _ _ _ | | 0
. |_ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _| |
. 8 |_ _ _ _ _ _ _ _ _|
. 31
.
The diagram contains A237590(16) = 27 parts.
For the construction of the spiral see A239660.
CROSSREFS
Row sums give A000203.
Row n has length A003056(n).
Column k starts in row A000217(k).
Nonzero terms give A237270.
The number of nonzero terms in row n is A237271(n).
Column 1 is A241838.
The triangle with n rows contain A237590(n) nonzero terms.
Cf. A296508 (analog for subparts).
KEYWORD
nonn,tabf
AUTHOR
Omar E. Pol, Apr 03 2018
STATUS
approved