OFFSET
1,2
COMMENTS
EXAMPLE
A corner of the array A178400 of sums of two primes:
4...5...7...9..13...
5...6...8..10..14...
7...8..10..12..14...
9..10..12..14..18...
Each of these P(i,j) is replaced by its rank when all the
numbers P(h,k) are jointly ranked, leaving A178431:
1...2...4...6...9...
2...3...5...7..10...
4...5...7...8..12...
6...7...8..10..13...
The number of distinct sums p+q <=13 is 9.
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Clark Kimberling, Dec 21 2010
STATUS
approved