OFFSET
2,1
COMMENTS
The first row of this array is row 2. The first column of this array is column 2.
LINKS
Diana Mecum, Table of n, a(n) for n=2..1276
FORMULA
If gcd(m,n) = 1 then a(m,n) = smallest prime factor of m times smallest prime factor of n, if gcd(m,n) > 1 then a(m,n) = min { smallest prime factor of m times smallest prime factor of n, smallest prime factor of gcd(m,n) }.
EXAMPLE
Array begins:
2 6 2 10 2 14 2 18 ...
6 3 6 15 6 ...
2 6 2 10 ...
10 15 ...
2 ...
MATHEMATICA
Table[k = 2; While[Or[CoprimeQ[#, k], CoprimeQ[n, k]] &[m - n + 2], k++]; k, {m, 2, 14}, {n, 2, m}] // Flatten (* Michael De Vlieger, Aug 01 2017 *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Leroy Quet, Jun 25 2008
EXTENSIONS
Edited by N. J. A. Sloane, Dec 28 2008
Extended by Ray Chandler, Jun 24 2009
STATUS
approved