A323624 - OEIS

A323624

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

0, 2, 5, 10, 16, 22, 32, 40, 50, 62, 73, 88, 101, 118, 134, 152, 170, 189, 210, 230, 253, 275, 299, 325, 351, 381, 406, 435, 465, 495, 527, 561, 593, 628, 663, 699, 737, 775, 813, 853, 895, 935, 981, 1021, 1068, 1113, 1156, 1205, 1253, 1302, 1352, 1401, 1454, 1502, 1557, 1609, 1664, 1723

(list; graph; refs; listen; history; text; internal format)

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..57.

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][i])+", ", end="")

CROSSREFS

For the grid read by antidiagonals see A323621.

For the first row of the grid see A323622.

For the second row of the grid see A323623.

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

Cf. A232499.

Sequence in context: A243971 A062472 A135061 * A348387 A086849 A131938

Adjacent sequences: A323621 A323622 A323623 * A323625 A323626 A323627

KEYWORD

nonn

AUTHOR

Rok Cestnik, Jan 20 2019

STATUS

approved