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A214272 Number of compositions of n where the difference between largest and smallest parts equals 3 and adjacent parts are unequal. 2
0, 2, 1, 8, 12, 18, 46, 69, 111, 208, 340, 539, 910, 1497, 2403, 3924, 6331, 10230, 16531, 26591, 42652, 68595, 110195, 176458, 282895, 452990, 725036, 1160067, 1855376, 2966265, 4740385, 7574822, 12099506, 19324253, 30856321, 49260709, 78631609, 125495919 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 4..2000

FORMULA

a(n) ~ c * d^n, where d = 1.59406371344091594038982448... is the root of the equation -3 + d - 3*d^2 - 3*d^4 + d^5 - 2*d^6 + d^7 - d^8 + d^9 = 0, and c = 0.63168955798354197444724247228159886565558573072349896252... . - Vaclav Kotesovec, Sep 01 2014

EXAMPLE

T(5) = 2: [4,1], [1,4].

T(6) = 1: [1,4,1].

T(7) = 8: [5,2], [4,2,1], [4,1,2], [2,5], [2,4,1], [2,1,4], [1,4,2], [1,2,4].

T(8) = 12: [4,3,1], [4,1,3], [4,1,2,1], [3,4,1], [3,1,4], [2,1,4,1], [1,4,3], [1,4,2,1], [1,4,1,2], [1,3,4], [1,2,4,1], [1,2,1,4].

CROSSREFS

Column k=3 of A214269.

Sequence in context: A118708 A055134 A137370 * A214273 A214274 A214275

Adjacent sequences:  A214269 A214270 A214271 * A214273 A214274 A214275

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 09 2012

STATUS

approved

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Last modified September 23 11:53 EDT 2020. Contains 337310 sequences. (Running on oeis4.)