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