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URL: https://oeis.org/A035041

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A035041
a(n) = 2^n - C(n,0) - C(n,1) - ... - C(n,8).
8
0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 11, 67, 299, 1093, 3473, 9949, 26333, 65536, 155382, 354522, 784626, 1695222, 3593934, 7507638, 15505590, 31746651, 64574877, 130712029, 263644133, 530396371, 1065084887, 2136022699, 4279934123, 8570386546, 17154657248, 34327470700
OFFSET
0,11
COMMENTS
a(n) is the number of binary strings of length n that contain at least five runs of ones. - Félix Balado, Sep 16 2025
LINKS
Félix Balado and Guénolé C. M. Silvestre, Systematic Enumeration of Fundamental Quantities Involving Runs in Binary Strings, arXiv:2602.10005 [math.CO], 2026. See p. 27.
Jürgen Eckhoff, Der Satz von Radon in konvexen Produktstrukturen II, Monat. f. Math., 73 (1969), 7-30.
Ângela Mestre and José Agapito, Square Matrices Generated by Sequences of Riordan Arrays, J. Int. Seq., Vol. 22 (2019), Article 19.8.4.
Index entries for linear recurrences with constant coefficients, signature (11,-54,156,-294,378,-336,204,-81,19,-2).
FORMULA
G.f.: x^9/((1 - 2*x)*(1 - x)^9).
a(n) = A000079(n) - A008861(n). - Alois P. Heinz, Feb 23 2026
MAPLE
a:=n->sum(binomial(n, j), j=9..n): seq(a(n), n=0..33); # Zerinvary Lajos, Jan 04 2007
MATHEMATICA
a=1; lst={}; s1=s2=s3=s4=s5=s6=s7=s8=s9=0; Do[s1+=a; s2+=s1; s3+=s2; s4+=s3; s5+=s4; s6+=s5; s7+=s6; s8+=s7; s9+=s8; AppendTo[lst, s9]; a=a*2, {n, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 10 2009 *)
Table[Sum[ Binomial[n, k], {k, 9, n}], {n, 0, 33}] (* Zerinvary Lajos, Jul 08 2009 *)
PROG
(Haskell)
a035041 n = a035041_list !! n
a035041_list = map (sum . drop 9) a007318_tabl
-- Reinhard Zumkeller, Jun 20 2015
CROSSREFS
Column m=9 of A055248.
Partial sums of A035040.
Sequence in context: A268458 A001808 A258479 * A125591 A092841 A165673
KEYWORD
nonn,easy
STATUS
approved