A341278 -id:A341278 - cp's OEIS frontend

A341363 Table read by antidiagonals: T(n, k) is the sum of the numbers inside the k-th square of size n X n when the square spiral is tiled with these squares, where each tile contains numbers which sum to the minimum possible value, and each number on the spiral can only be in one tile.

1, 2, 10, 3, 48, 45, 4, 60, 276, 136, 5, 68, 321, 928, 325, 6, 80, 368, 1040, 2349, 666, 7, 92, 384, 1168, 2575, 4984, 1225, 8, 100, 429, 1296, 2825, 5382, 9391, 2080, 9, 124, 456, 1388, 3075, 5816, 10030, 16228, 3321, 10, 128, 554, 1656, 3627, 6250, 10718, 17190, 26257, 5050

Offset: 1

Scott R. Shannon, Feb 10 2021

The terms for a given n tend to have larger jumps in value at one more than the square of the odd numbers, i.e., at k = (2*t+1)^2 + 1, t >= 0, due to the previous square filling a grid of squares containing (2*t+1)^2 squares. This forces the next square to move further away from the origin and into spiral arms containing larger numbers.

See A341278 for the smallest spiral number not covered by any square in each n X n tiling.

			The table begins:
     1,     2,     3,     4,     5,     6,     7,     8,     9,     10, ...
    10,    48,    60,    68,    80,    92,   100,   124,   128,    156, ...
    45,   276,   321,   368,   384,   429,   456,   554,   702,    803, ...
   136,   928,  1040,  1168,  1296,  1388,  1656,  1696,  1858,   2876, ...
   325,  2349,  2575,  2825,  3075,  3627,  3935,  4243,  4415,   7740, ...
   666,  4984,  5382,  5816,  6250,  8456,  9188,  9576, 10154,  14204, ...
  1225,  9391, 10030, 10718, 11406, 15006, 16260, 16737, 17627,  27701, ...
  2080, 16228, 17190, 18216, 19242, 24856, 26856, 27392, 28692,  49240, ...
  3321, 26257, 27636, 29096, 30556, 38998, 42010, 42561, 44383,  81527, ...
  5050, 40344, 42246, 44248, 46250, 58560, 62892, 63400, 65870, 127660, ...
  7381, 59459, 62002, 64666, 67330, 84806, 90808, 91201, 94459, 191129, ...
  ...
.
a(2,1) = 10 as the first square of size 2 X 2 is placed such that it covers the numbers 1,2,3,4, which sum to 10. This is the minimum possible sum.
a(2,2) = 48 as the second square of size 2 X 2 is placed such that it covers the numbers 5,6,18,19, which sum to 48. This is the minimum possible sum for such a square which does not use the previously covered numbers 1,2,3,4.
a(2,3) = 60 as the third square of size 2 X 2 is placed such that it covers the numbers 7,8,22,23, which sum to 60. This is the minimum possible sum for such a square which does not use the previously covered numbers 1,2,3,4,5,6,18,19.

Scott R. Shannon, Image for n=2, k = 1..2000. The image can be zoomed in to see the numbers of the square spiral. In this and other images the colors are graduated around the spectrum to show the squares relative placement order.
Scott R. Shannon, Image for n=4, k = 1..1000.
Scott R. Shannon, Image for n=5, k = 1..1000.
Scott R. Shannon, Image for n=7, k = 1..1000.
Scott R. Shannon, Image for n=10, k = 1..500.

Cf. A341160, A341327, A340974, A174344, A274923, A296030, A275161.

T(1,k) = k.

T(n,1) = n^2*(n^2+1)/2 = A000217(n^2).

A343031 Table read by antidiagonals: T(n, k) is the sum of the numbers on the k-th line of length n when these lines are drawn on the square spiral, where each line contains numbers which sum to the minimum possible value, and each number on the spiral can only be in one line.

Original entry on oeis.org

1, 2, 3, 3, 7, 9, 4, 11, 12, 20, 5, 15, 24, 24, 39, 6, 19, 33, 34, 42, 67, 7, 23, 42, 58, 54, 71, 107, 8, 27, 54, 74, 75, 81, 110, 160, 9, 31, 66, 90, 115, 105, 122, 164, 229, 10, 35, 75, 110, 140, 141, 143, 174, 232, 315, 11, 39, 84, 130, 165, 201, 183, 198, 244, 319, 421

Offset: 0

Scott R. Shannon, Apr 03 2021

Lines of length zero (a single point) and one (two points) can cover the entire square spiral without missing any numbers.
For lines with even numbered length the pattern of lines is very regular, with all lines along the spiral lines of the square spiral, and regular triangles of uncovered numbers along the four diagonals of the spiral. See the linked images with even n.
For odd length lines the pattern formed is more random, with some quadrants have regions, or the entire quadrant, with lines that are orthogonal to the spiral lines, and the triangles of uncovered values becomes more random along the spiral diagonals. See the linked images with odd n.
For n>=2 the smallest spiral number that is not covered by any line is n^2+4n+4.

			The square spiral used is:
.
  17--16--15--14--13   .
   |               |   .
  18   5---4---3  12   29
   |   |       |   |   |
  19   6   1---2  11   28
   |   |           |   |
  20   7---8---9--10   27
   |                   |
  21--22--23--24--25--26
.
The table begins:
    1,   2,   3,   4,   5,   6,   7,   8,    9,   10,   11,   12, ...
    3,   7,  11,  15,  19,  23,  27,  31,   35,   39,   43,   47, ...
    9,  12,  24,  33,  42,  54,  66,  75,   84,   96,  105,  114, ...
   20,  24,  34,  58,  74,  90, 110, 130,  154,  178,  194,  210, ...
   39,  42,  54,  75, 115, 140, 165, 195,  225,  260,  295,  335, ...
   67,  71,  81, 105, 141, 201, 237, 273,  315,  357,  405,  453, ...
  107, 110, 122, 143, 183, 238, 322, 371,  420,  476,  532,  595, ...
  160, 164, 174, 198, 234, 294, 372, 484,  548,  612,  684,  756, ...
  229, 232, 244, 265, 305, 360, 444, 549,  693,  774,  855,  945, ...
  315, 319, 329, 353, 389, 449, 527, 639,  775,  955, 1055, 1155, ...
  421, 424, 436, 457, 497, 552, 636, 741,  885, 1056, 1276, 1397, ...
  548, 552, 562, 586, 622, 682, 760, 872, 1008, 1188, 1398, 1662, ...

Scott R. Shannon, Image for n=1, k=1..4000. The image can be zoomed in to see the numbers of the square spiral. In this and other images the colors are graduated around the spectrum to show the lines relative placement order.
Scott R. Shannon, Image for n=2, k=1..2000.
Scott R. Shannon, Image for n=3, k=1..2000.
Scott R. Shannon, Image for n=4, k=1..2000.
Scott R. Shannon, Image for n=9, k=1..2000.
Scott R. Shannon, Image for n=10, k=1..2000.
Scott R. Shannon, Image for n=17, k=1..2000.
Scott R. Shannon, Image for n=20, k=1..2000.
Scott R. Shannon, Image for n=21, k=1..2000.

Cf. A340974, A341160, A341363, A341278, A341327, A174344, A274923, A296030, A275161.

T(0,k) = k.

T(1,k) = 3 + 4(k-1).

cp's OEIS Frontend

A341363 Table read by antidiagonals: T(n, k) is the sum of the numbers inside the k-th square of size n X n when the square spiral is tiled with these squares, where each tile contains numbers which sum to the minimum possible value, and each number on the spiral can only be in one tile.

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