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⇱ A133551 - OEIS

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A133551
Number of length n binary sequences with at most 3 of every 6 adjacent bits set.
8
1, 2, 4, 8, 15, 26, 42, 74, 132, 236, 421, 747, 1314, 2318, 4101, 7263, 12864, 22773, 40291, 71272, 126099, 223144, 394895, 698823, 1236609, 2188185, 3872000, 6851631, 12124307, 21454602, 37964931, 67180507, 118878510, 210360283, 372241362, 658697067
OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,1,0,0,1,3,0,-3,-1,0,0,-3,-1,3,0,0,0,1,0,-1).
FORMULA
G.f.: -(x^19 +x^18 -x^16 -x^15 -3*x^13 -2*x^12 +2*x^11 +4*x^10 +2*x^9 +x^8 +4*x^7 +4*x^6 -2*x^5 -3*x^4 -2*x^3 -x^2-x-1) / ((x-1) *(x+1) *(x^18 -3*x^12 +x^11 +x^9 +2*x^7 +3*x^6 +2*x^5 +x^3 +x -1)). - Alois P. Heinz, May 29 2020
CROSSREFS
Sequence in context: A204555 A000125 A129961 * A114226 A210063 A187154
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Dec 24 2007
STATUS
approved