A152905 Irregular triangle read by rows, numbers in A007318 repeated .

1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 3, 3, 3, 3, 1, 1, 1, 1, 4, 4, 6, 6, 4, 4, 1, 1, 1, 1, 5, 5, 10, 10, 10, 10, 5, 5, 1, 1, 1, 1, 6, 6, 15, 15, 20, 20, 15, 15, 6, 6, 1, 1, 1, 1, 7, 7, 21, 21, 35, 35, 35, 35, 21, 21, 7, 7, 1, 1, 1, 1, 8, 8, 28, 28, 56, 56, 70, 70, 56, 56, 28, 28, 8, 8, 1, 1

Offset: 0

Author

Philippe Deléham, Dec 14 2008

Keywords

• nonn
• tabf

Comments

Diagonal sums : A097333 .

Examples

			Triangle begins : 1,1 ; 1,1,1,1 ; 1,1,2,2,1,1 ; 1,1,3,3,3,3,1,1, ; 1,1,4,4,6,6,4,4,1,1 ; 1,1,5,5,10,10,10,10,5,5,1,1 ; ...
		

Crossrefs

Cf. A000079,

Formula

Sum_{k, 0<=k<=2n}T(n,k)=2^(n+1).

Extensions

Typo in a(74) corrected by Georg Fischer, May 26 2024