A188524 In base-2 lunar arithmetic, out of all odd numbers of length n, it appears that 111..1 (with n ones) has the most lunar divisors; the sequence gives the number of lunar divisors of the runner-up.

2, 2, 4, 4, 6, 10, 16, 31, 55, 100, 185, 345, 644, 1209, 2274, 4298, 8145, 15469, 29454, 56213, 107489, 205925, 395190, 759621, 1462282, 2818799, 5440705, 10513994, 20340794, 39393580, 76368240, 148185145, 287791544, 559386196, 1088144064, 2118283567, 4126561528, 8044217224

Offset

3,1

Links

Table of n, a(n) for n=3..40.

D. Applegate, M. LeBrun and N. J. A. Sloane, Dismal Arithmetic [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing]

Index entries for sequences related to dismal (or lunar) arithmetic

Example

For n = 3, 4, 5 the runner-ups are 101, 1101 or 1011, 11011; thereafter they appear to be the numbers 111...101 or their reversals (see A188288).

Crossrefs

Cf. A079500, A188288.

Sequence in context: A131733 A128745 A332891 * A126064 A066813 A320194

Adjacent sequences: A188521 A188522 A188523 * A188525 A188526 A188527

Keyword

nonn,base

Author

N. J. A. Sloane, Apr 16 2011

Status

approved