A301454 Number of strictly log-concave permutations of {1,...,n}.
1, 1, 2, 4, 6, 8, 10, 12, 12, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
Offset: 0
Links
- Pontus Andersson (von Brömssen), Log-concave permutations, Manuscript, 2002.
- Eric Weisstein's World of Mathematics, Logarithmically Concave Sequence
- Index entries for linear recurrences with constant coefficients, signature (1).
Crossrefs
Cf. A300781.
Programs
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Mathematica
CoefficientList[Series[(4*x^9 - 2*x^7 - 2*x^6 - 2*x^5 - 2*x^4 - 2*x^3 - x^2 - 1)/(x - 1), {x, 0, 100}], x] (* Wesley Ivan Hurt, Dec 26 2023 *) -
PARI
Vec((4*x^9 -2*x^7 -2*x^6 -2*x^5 -2*x^4 -2*x^3 -x^2 -1)/(x-1) + O(x^100)) \\ Felix Fröhlich, Mar 23 2018
Formula
G.f.: (4*x^9 -2*x^7 -2*x^6 -2*x^5 -2*x^4 -2*x^3 -x^2 -1)/(x-1).
Comments