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A287835 Number of words of length n over the alphabet {0,1,...,10} such that no two consecutive terms have distance 4. 0
1, 11, 107, 1043, 10169, 99149, 966719, 9425675, 91901945, 896059709, 8736735695, 85184670011, 830565128489, 8098152315149, 78958372642847, 769857662314475, 7506244118089817, 73187166301583837, 713587411625345903, 6957599532298617755, 67837787583138657929 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..20.

Index entries for linear recurrences with constant coefficients, signature (10,-1,-14)

FORMULA

For n>3, a(n) = 10*a(n-1) - a(n-2) - 14*a(n-3), a(0)=1, a(1)=11, a(2)=107, a(3)=1043.

G.f.: (1 + x - 2 x^2 - 2 x^3)/(1 - 10 x + x^2 + 14 x^3).

MATHEMATICA

LinearRecurrence[{10, -1, -14}, {1, 11, 107, 1043}, 20]

PROG

(Python)

def a(n):

.if n in [0, 1, 2, 3]:

..return [1, 11, 107, 1043][n]

.return 10*a(n-1) - a(n-2) - 14*a(n-3)

CROSSREFS

Cf. A040000, A003945, A083318, A078057, A003946, A126358, A003946, A055099, A003947, A015448, A126473. A287804-A287819. A287825-A287839.

Sequence in context: A140617 A224717 A163413 * A001721 A193308 A080158

Adjacent sequences:  A287832 A287833 A287834 * A287836 A287837 A287838

KEYWORD

nonn,easy

AUTHOR

David Nacin, Jun 07 2017

STATUS

approved

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Last modified June 17 13:43 EDT 2021. Contains 345080 sequences. (Running on oeis4.)