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 A317612 For k >= 1, fill a k X k square with the numbers 1 to k^2 by rows left to right and top to bottom; then read the square by a square clockwise spiral beginning at the top left and spiraling inwards. 0
 1, 1, 2, 4, 3, 1, 2, 3, 6, 9, 8, 7, 4, 5, 1, 2, 3, 4, 8, 12, 16, 15, 14, 13, 9, 5, 6, 7, 11, 10, 1, 2, 3, 4, 5, 10, 15, 20, 25, 24, 23, 22, 21, 16, 11, 6, 7, 8, 9, 14, 19, 18, 17, 12, 13, 1, 2, 3, 4, 5, 6, 12, 18, 24, 30, 36, 35, 34, 33, 32, 31, 25, 19, 13, 7, 8, 9, 10, 11, 17, 23, 29, 28, 27, 26, 20, 14, 15, 16, 22, 21, 1, 2, 3, 4, 5, 6, 7, 14, 21, 28, 35, 42, 49, 48, 47, 46, 45, 44, 43 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Inspired by A317186. The final term in the k X k spiral is A031878(k+1). LINKS EXAMPLE 1 => 1; .   1---2       |   3---4  =>  1, 2, 4, 3; .   1---2---3           |   4---5   6   |       |   7---8---9  =>  1, 2, 3, 6, 9, 8, 7, 4, 5; .    1---2---3---4                |    5---6---7   8    |       |   |    9  10--11  12    |           |   13--14--15--16 .   => 1, 2, 3, 4, 8, 12, 16, 15, 14, 13, 9, 5, 6, 7, 11, 10; .    1---2---3---4---5                    |    6---7---8---9  10    |           |   |   11  12--13  14  15    |   |       |   |   16  17--18--19  20    |               |   21--22--23--24--25 .   => 1, 2, 3, 4, 5, 10, 15, 20, 25, 24, 23, 22, 21, 16, 11, 6, 7, 8, 9, 14, 19, 18, 17, 12, 13; .    1---2---3---4---5---6                        |    7---8---9--10--11  12    |               |   |   13  14--15--16  17  18    |   |       |   |   |   19  20  21--22  23  24    |   |           |   |   25  26--27--28--29  30    |                   |   31--32--33--34--35--36 .   => 1, 2, 3, 4, 5, 6, 12, 18, 24, 30, 36, 35, 34, 33, 32, 31, 25, 19, 13, 7, 8, 9, 10, 11, 17, 23, 29, 28, 27, 26, 20, 14, 15, 16, 22, 21; MATHEMATICA (* To form an n X n square table which begins left to right, then top to bottom *) a[i_, j_, n_] := j + n*(i - 1); f[n_] := Table[ a[i, j, n], {i, n}, {j, n}] CROSSREFS Cf. A031878, A317186. Sequence in context: A227862 A229802 A106581 * A070402 A125941 A347270 Adjacent sequences:  A317609 A317610 A317611 * A317613 A317614 A317615 KEYWORD easy,nonn AUTHOR George E. Laham II and Robert G. Wilson v, Aug 01 2018 STATUS approved

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Last modified December 9 03:18 EST 2021. Contains 349625 sequences. (Running on oeis4.)