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A152514 1/7 of the number of permutations of 6 indistinguishable copies of 1..n with exactly 3 local maxima. 1
0, 50, 42035, 22286180, 10637332433, 4951385566862, 2291336707020095, 1058974724436063848, 489282897651319234589, 226052182024142033107730, 104436435218150212780973867, 48249663449218668484434011660, 22291347308935948403947280066153, 10298602712004866151067473095589974 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..200

Index entries for linear recurrences with constant coefficients, signature (651,-98049,5130937,-81120186,508243680,-1118136096).

FORMULA

From Colin Barker, Jul 19 2020: (Start)

G.f.: x^2*(50 + 9485*x - 176155*x^2 - 6027882*x^3 - 3111696*x^4) / ((1 - 7*x)^3*(1 - 84*x)^2*(1 - 462*x)).

a(n) = 651*a(n-1) - 98049*a(n-2) + 5130937*a(n-3) - 81120186*a(n-4) + 0*a(n-5) - 0*a(n-6) for n>6.

(End)

PROG

(PARI) \\ PeaksBySig defined in A334774.

a(n) = {PeaksBySig(vector(n, i, 6), [2])[1]/7} \\ Andrew Howroyd, May 12 2020

(PARI) concat(0, Vec(x^2*(50 + 9485*x - 176155*x^2 - 6027882*x^3 - 3111696*x^4) / ((1 - 7*x)^3*(1 - 84*x)^2*(1 - 462*x)) + O(x^15))) \\ Colin Barker, Jul 19 2020

CROSSREFS

Cf. A152513, A334774.

Sequence in context: A173170 A146518 A229670 * A015062 A015038 A152515

Adjacent sequences:  A152511 A152512 A152513 * A152515 A152516 A152517

KEYWORD

nonn,easy

AUTHOR

R. H. Hardin, Dec 06 2008

EXTENSIONS

Terms a(7) and beyond from Andrew Howroyd, May 12 2020

STATUS

approved

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Last modified March 2 06:37 EST 2021. Contains 341744 sequences. (Running on oeis4.)