A143069 Least number k such that n*k has the fewest possible ones in its binary expansion.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 5, 1, 1, 1, 1, 1, 27, 1, 1, 3, 3, 1, 41, 5, 19, 1, 565, 1, 1, 1, 1, 1, 1, 1, 7085, 27, 7, 1, 25, 1, 3, 3, 1, 3, 11, 1, 1, 41, 1, 5, 1266205, 19, 7, 1, 9, 565, 9099507, 1, 17602325, 1, 1, 1, 1, 1, 128207979, 1, 1, 1, 119, 1, 1, 7085, 1, 27, 5, 7, 13

Offset

1,11

Comments

a(n)=1 indicates that n is a sturdy number (A125121); that is, no multiple of n has fewer ones than the binary expansion of n. A086342(n) gives the least possible number of ones in the binary expansion of a multiple of n. Compare with A143073.

Links

T. D. Noe, Table of n, a(n) for n=1..1000

Trevor Clokie et al., Computational Aspects of Sturdy and Flimsy Numbers, arxiv preprint arXiv:2002.02731 [cs.DS], February 7 2020.

Crossrefs

Sequence in context: A197152 A337668 A176907 * A010286 A340074 A344592

Adjacent sequences: A143066 A143067 A143068 * A143070 A143071 A143072

Keyword

nonn

Author

T. D. Noe, Jul 22 2008

Status

approved