A317781 Number of binary words of length n containing exactly two (possibly overlapping) occurrences of the subword 01101.
1, 4, 13, 35, 92, 230, 562, 1333, 3106, 7114, 16090, 35968, 79637, 174812, 380903, 824469, 1774122, 3797436, 8089574, 17158409, 36250415, 76309260, 160102335, 334877607, 698461293, 1452964434, 3015112497, 6242510786, 12896941964, 26591579894, 54724833014
Offset: 8
Links
- Alois P. Heinz, Table of n, a(n) for n = 8..2000
- Index entries for linear recurrences with constant coefficients, signature (6,-12,5,18,-39,33,6,-42,47,-21,-9,20,-15,6,-1).
Crossrefs
Column k=2 of A277751.
Formula
G.f.: x^8*(x-1)^2/(x^5-2*x^4+x^3-2*x+1)^3.