A372768 The number of shaded cells in all compositions of n when light shines from the northwest. Here compositions are represented by stacked columns of adjacent cells.

0, 1, 4, 13, 34, 85, 199, 454, 1011, 2220, 4813, 10351, 22104, 46948, 99266, 209113

Offset: 1

Author

Michael Mays, May 12 2024

Keywords

• nonn
• more

Examples

			For n=4, the composition 1+3 produces 3 shaded cells, 2+2 produces 1, 3+1 produces 2, 1+1+2 produces 1, 4 produces 6, and the others have no shaded cells, for a total of 13, so a(4) = 13.
		

Links

• A. Blecher, A. Knopfmacher, and M. E. Mays, Shade in compositions of integers, Journal of Integer Sequences, Vol. 27 (2024), Article 24.5.6.

Crossrefs

Cf. A366157.