login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

A164437
Number of binary strings of length n with no substrings equal to 0000, 0101, or 1111.
1
1, 2, 4, 8, 13, 22, 37, 62, 104, 174, 292, 490, 821, 1376, 2308, 3870, 6487, 10876, 18237, 30576, 51261, 85946, 144102, 241600, 405064, 679140, 1138659, 1909078, 3200774, 5366466, 8997477, 15085240, 25292069, 42404978, 71096617, 119201278, 199854120, 335077546
OFFSET
0,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..2000 (terms n=4..500 from R. H. Hardin)
FORMULA
G.f.: -(x+1)^2*(x^2+1)^3/(x^6+2*x^5+3*x^4+2*x^3-1). - R. J. Mathar, Jan 19 2011
CROSSREFS
Sequence in context: A164441 A338761 A023600 * A164428 A164507 A164414
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Aug 14 2009
EXTENSIONS
a(0)-a(3) from Alois P. Heinz, Jun 11 2021
STATUS
approved