A323623 The second row of the order of square grid cells touched by a circle expanding from the middle of a cell.

1, 2, 4, 7, 10, 14, 19, 24, 30, 36, 43, 49, 58, 66, 75, 85, 95, 105, 116, 128, 139, 152, 164, 178, 193, 206, 222, 236, 251, 268, 285, 302, 318, 338, 357, 377, 395, 416, 437, 457, 478, 501, 522, 547, 569, 591, 617, 641, 667, 691, 717, 746, 771, 799, 827, 856, 885, 914, 943, 974, 1004, 1034, 1067

Offset

0,2

Comments

Related to, but not the same as the case with the circle centered at the corner of a cell, see A232499.

Links

Table of n, a(n) for n=0..62.

Rok Cestnik, Visualization

Prog

(Python)
N = 12
from math import sqrt
# the distance to the edge of each cell
edges = [[-1 for j in range(N)] for i in range(N)]
edges[0][0] = 0
for i in range(1, N):
    edges[i][0] = i-0.5
    edges[0][i] = i-0.5
for i in range(1, N):
    for j in range(1, N):
        edges[i][j] = sqrt((i-0.5)**2+(j-0.5)**2)
# the values of the distances
values = []
for i in range(N):
    for j in range(N):
        values.append(edges[i][j])
values = list(set(values))
values.sort()
# the cell order
board = [[-1 for j in range(N)] for i in range(N)]
count = 0
for v in values:
    for i in range(N):
        for j in range(N):
            if(edges[i][j] == v):
                board[i][j] = count
    count += 1
# print out the sequence
for i in range(N):
    print(str(board[i][1])+" ", end="")

Crossrefs

For the grid read by antidiagonals see A323621.

For the first row of the grid see A323622.

For the diagonal of the grid see A323624.

For the (2,1) diagonal of the grid see A323625.

Cf. A232499.

Sequence in context: A145106 A127723 A076268 * A055607 A024512 A047808

Adjacent sequences: A323620 A323621 A323622 * A323624 A323625 A323626

Keyword

nonn

Author

Rok Cestnik, Jan 20 2019

Status

approved