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A028295 a(n) = n^6 - (883/60)*n^5 + (157/3)*n^4 + (2155/12)*n^3 - (4570/3)*n^2 + (42767/15)*n - 967. 0
133, 1903, 10561, 38015, 106461, 252737, 533397, 1030505, 1858149, 3169675, 5165641, 8102491, 12301949, 18161133, 26163389, 36889845, 51031685, 69403143, 92955217, 122790103, 160176349, 206564729, 263604837, 333162401, 417337317, 518482403, 639222873 (list; graph; refs; listen; history; text; internal format)
OFFSET

6,1

COMMENTS

Old name was: "Number of stacks of n pikelets, distance 6 flips from a well-ordered stack".

LINKS

Table of n, a(n) for n=6..32.

Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).

FORMULA

G.f.: x^6*(-133 - 972*x - 33*x^2 + 604*x^3 - 187*x^4 - 2*x^5 + 3*x^6) / (x-1)^7. - R. J. Mathar, Jun 21 2011

MATHEMATICA

a[n_] := n^6 - (883/60) n^5 + (157/3) n^4 + (2155/12) n^3 - (4570/3) n^2 + (42767/15) n - 967; Table[a[n], {n, 6, 32}] (* or *)

CoefficientList[ Series[x^6 (3x^6 - 2x^5 - 187x^4 + 604x^3 - 33x^2 - 972x - 133)/(x - 1)^7, {x, 0, 26}], x] (* or *)

LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {133, 1903, 10561, 38015, 106461, 252737, 533397}, 27] (* Robert G. Wilson v, Jul 29 2018 *)

CROSSREFS

Sequence in context: A274175 A038491 A020265 * A262121 A254684 A133240

Adjacent sequences:  A028292 A028293 A028294 * A028296 A028297 A028298

KEYWORD

nonn,easy

AUTHOR

R. K. Guy

EXTENSIONS

Entry revised by N. J. A. Sloane, Jun 15 2014

a(17)-a(32) from Robert G. Wilson v, Jul 29 2018

STATUS

approved

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Last modified December 16 07:12 EST 2018. Contains 318158 sequences. (Running on oeis4.)