login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A121880
a(n) = 2^n - A122536(n).
7
0, 2, 4, 10, 20, 44, 88, 182, 364, 738, 1476, 2972, 5944, 11924, 23848, 47768, 95536, 191214, 382428, 765136, 1530272, 3061104, 6122208, 12245530, 24491060, 48984342, 97968684, 195941804, 391883608, 783776080, 1567552160, 3135122038, 6270244076
OFFSET
1,2
COMMENTS
Number of binary sequences of length n with curling number > 1. See A122536 for much more information.
LINKS
B. Chaffin, J. P. Linderman, N. J. A. Sloane and Allan Wilks, On Curling Numbers of Integer Sequences, arXiv:1212.6102 [math.CO], 2012-2013.
B. Chaffin, J. P. Linderman, N. J. A. Sloane and Allan Wilks, On Curling Numbers of Integer Sequences, Journal of Integer Sequences, Vol. 16 (2013), Article 13.4.3.
Daniel Gabric, Jeffrey Shallit, Borders, Palindrome Prefixes, and Square Prefixes, arXiv:1906.03689 [cs.DM], 2019.
CROSSREFS
Cf. A122536. Similar to but different from A094536.
See also A093370.
Sequence in context: A026666 A325508 A238439 * A094536 A323445 A307768
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 21 2006
STATUS
approved