1,2

a(5)=11 because the following are the 11 coverings of {1...5}, each one of which only uses a single set and its translations:

{{1},{2},{3},{4},{5}}

{{1,2},{3,4},{4,5}}

{{1,2},{2,3},{3,4},{4,5}}

{{1,2},{2,3},{4,5}}

{{1,3},{2,4},{3,5}}

{{1,2,3},{2,3,4},{3,4,5}}

{{1,2,3},{3,4,5}}

{{1,2,4},{2,3,5}}

{{1,3,4},{2,4,5}}

{{1,2,3,4},{2,3,4,5}}

{{1,2,3,4,5}}

Cf. A096154, A096203.

Sequence in context: A027214 A132831 A007477 this_sequence A036653 A123769 A093304

Adjacent sequences: A096199 A096200 A096201 this_sequence A096203 A096204 A096205

nonn

Jon Wild (wild(AT)music.mcgill.ca), Jul 27 2004