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A279965
Square array read by antidiagonals upwards in which each term is the number of prior elements in the same row, column, diagonal, or antidiagonal whose parity is the same as the parity of n.
2
0, 1, 1, 1, 3, 1, 2, 1, 5, 2, 2, 2, 5, 3, 4, 3, 4, 3, 8, 4, 4, 3, 5, 3, 7, 3, 9, 4, 4, 3, 8, 6, 6, 8, 6, 11, 4, 4, 8, 8, 5, 9, 7, 7, 7, 5, 6, 5, 6, 8, 8, 12, 9, 7, 8, 5, 7, 5, 7, 8, 12, 9, 13, 5, 15, 8, 6, 5, 10, 9, 6, 12, 8, 13, 11, 8, 12, 14
OFFSET
1,5
EXAMPLE
The array is constructed along its antidiagonals, in the following way:
.
a(1) a(3) a(6) a(10)
a(2) a(5) a(9)
a(4) a(8)
a(7)
.
----------------------------------------------------------
n a(n) array
----------------------------------------------------------
1 0 0
.
2 1 0
1
.
3 1 0 1
1
.
4 1 0 1
1
1
.
5 3 0 1
1 3
1
.
6 1 0 1 1
1 3
1
For example, a(5) = 3 because 5 has the same parity as a(2), a(3), and a(4), which are in the same row, column, and antidiagonal, respectively.
CROSSREFS
Cf. A279968 for the similar array giving the number of prior elements of opposite parity.
Sequence in context: A347395 A059807 A214208 * A285121 A295935 A318323
KEYWORD
nonn,tabl
AUTHOR
Alec Jones, Dec 24 2016
STATUS
approved