A039671 Row sums up to the main diagonal of the "postage stamp" array (n,m >= 0) defined in A007059.

1, 1, 3, 8, 21, 53, 130, 310, 724, 1661, 3757, 8398, 18588, 40800, 88918, 192592, 414907, 889631, 1899554, 4040864, 8567342, 18109698, 38176280, 80278798, 168432854, 352658013, 736977583, 1537420460, 3202035086, 6658948608

Offset: 0

Author

Richard L. Ollerton and Eirwyn L. Ollerton

Keywords

• easy
• nonn

Examples

			a(0)=1, a(1)=0+1=1, a(2)=0+1+2=3, a(3)=0+1+3+4=8.
		

Crossrefs

Cf. A007059.

Programs

Mathematica

f[ n_, m_ ] := f[ n, m ]=Which[ n>0, Sum[ f[ n-i, m ], {i, 1, m} ], n<0, 0, n==0, 1 ] Table[ Sum[ f[ n, j ], {j, 0, n} ], {n, 0, 30} ]

Formula

Conjecture: a(n) = Sum_{k=1..n} A126198(n,k), for n > 0. - L. Edson Jeffery, Nov 29 2013