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

1,3

Links

Table of n, a(n) for n=1..16.

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

Example

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.

Crossrefs

Cf. A366157.

Sequence in context: A212149 A357284 A208740 * A127981 A296303 A089453

Adjacent sequences: A372765 A372766 A372767 * A372769 A372770 A372771

Keyword

nonn,more

Author

Michael Mays, May 12 2024

Status

approved