A178400 Sums of two primes, an array by antidiagonals.

4, 5, 5, 6, 7, 7, 8, 8, 9, 9, 10, 10, 10, 12, 12, 13, 13, 14, 14, 14, 15, 15, 16, 16, 16, 16, 18, 18, 18, 18, 19, 19, 20, 20, 20, 20, 21, 21, 22, 22, 22, 22, 22, 24, 24, 24, 24, 24, 24, 25, 25, 26, 26, 26, 26, 26, 28, 28, 28, 28, 30, 30, 30, 30, 30, 30, 31

Offset: 1

Author

Clark Kimberling, Dec 21 2010

Keywords

• nonn
• tabl

Comments

The joint-rank array of this array is A178431.

Examples

			Northwest corner:
4....5....7....9...13...
5....6....8...10...12...
7....8...10...12...16...
9...10...12...14...14...
T(1,1)=2+2=4.
		

Crossrefs

Cf. A000040, A014092.

Formula

T(i,j)=p(i)+p(j), where p=(2,3,5,7,...)=A000040.