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A159923 Rectangular array read by antidiagonals: a(m,n) = greatest noncomposite (1 or prime) that divides both m and n. 1
1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 3, 1, 1, 3, 1, 1, 1, 2, 1, 2, 5, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 2, 1, 3, 1, 2, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 7, 2, 1, 2, 1, 2, 1, 1, 1, 3, 1, 5, 3, 1, 1, 3, 5, 1, 3, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

The array is symmetric along the diagonal, so there is a triangular version with the same amount of information that reads the array along rows up to the diagonal: 1,1,2,1,1,3,1,2,1,2,1,1,1,1,5,1,... - R. J. Mathar, Apr 29 2009

LINKS

Table of n, a(n) for n=1..105.

MAPLE

A159923 := proc(n, m) local g; for g from max(n, m) to 2 by -1 do if isprime(g) and (n mod g) = 0 and (m mod g) = 0 then RETURN(g) ; fi; od: RETURN(1) ; end: for d from 2 to 22 do for m from 1 to d-1 do n := d-m ; printf("%d, ", A159923(n, m)) ; od: od: # R. J. Mathar, Apr 29 2009

CROSSREFS

Sequence in context: A124060 A329720 A140194 * A287957 A003989 A091255

Adjacent sequences:  A159920 A159921 A159922 * A159924 A159925 A159926

KEYWORD

nonn,tabl

AUTHOR

Leroy Quet, Apr 26 2009

EXTENSIONS

More terms from R. J. Mathar, Apr 29 2009

STATUS

approved

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Last modified June 18 20:45 EDT 2021. Contains 345121 sequences. (Running on oeis4.)