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A143901 Rectangular array R by antidiagonals: R(m,n) = floor((m*n+1)/2). 1
1, 1, 1, 2, 2, 2, 2, 3, 3, 2, 3, 4, 5, 4, 3, 3, 5, 6, 6, 5, 3, 4, 6, 8, 8, 8, 6, 4, 4, 7, 9, 10, 10, 9, 7, 4, 5, 8, 11, 12, 13, 12, 11, 8, 5, 5, 9, 12, 14, 15, 15, 14, 12, 9, 5, 6, 10, 14, 16, 18, 18, 18, 16, 14, 10, 6, 6, 11, 15, 18, 20, 21, 21, 20, 18, 15, 11, 6, 7, 12, 17, 20, 23, 24, 25, 24 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Old name was: R(m,n) = number of white squares.

LINKS

Table of n, a(n) for n=1..86.

EXAMPLE

Northwest corner:

1 1 2 2 3 3 4 4

1 2 3 4 5 6 7 8

2 3 5 6 8 9 11 12

2 4 6 8 10 12 14 16

CROSSREFS

Cf. A143902.

Antidiagonal sums: (1,2,6,10,19,...)=A005993.

Diagonals: A000982, A000217, A007590, A000096, A116940.

Rows and columns: A004526, A000027, A007494, A005843, A047218 et al.

Sequence in context: A093450 A096198 A103183 * A115263 A055894 A224713

Adjacent sequences:  A143898 A143899 A143900 * A143902 A143903 A143904

KEYWORD

nonn,tabl

AUTHOR

Clark Kimberling, Sep 04 2008

EXTENSIONS

Entry revised by N. J. A. Sloane, Jun 12 2015

STATUS

approved

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Last modified October 15 15:14 EDT 2019. Contains 328030 sequences. (Running on oeis4.)