A026046 - OEIS

A026046

a(n) = dot_product(1,2,...,n)*(6,7,...,n,1,2,3,4,5).

76, 105, 144, 195, 260, 341, 440, 559, 700, 865, 1056, 1275, 1524, 1805, 2120, 2471, 2860, 3289, 3760, 4275, 4836, 5445, 6104, 6815, 7580, 8401, 9280, 10219, 11220, 12285, 13416, 14615, 15884, 17225, 18640, 20131, 21700, 23349, 25080, 26895, 28796, 30785, 32864, 35035, 37300

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OFFSET

6,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 6..1000

Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

FORMULA

a(n) = n(n^2-6n+38)/3. - Ralf Stephan, Apr 30 2004

G.f.: x^6*(76-199*x+180*x^2-55*x^3)/(1-x)^4. - Colin Barker, Sep 17 2012

MATHEMATICA

Table[n(n^2 - 6n + 38)/3, {n, 6, 100}] (* Stefan Steinerberger, Apr 14 2006 *)

CoefficientList[Series[(76 - 199 x + 180 x^2 - 55 x^3)/(1 - x)^4, {x, 0, 60}], x] (* Vincenzo Librandi, Oct 17 2013 *)

Table[Range[n].Join[Range[6, n], Range[5]], {n, 6, 50}] (* or *) LinearRecurrence[{4, -6, 4, -1}, {76, 105, 144, 195}, 50] (* Harvey P. Dale, Mar 12 2023 *)

PROG

(Magma) [n*(n^2-6*n+38)/3: n in [6..60]]; // Vincenzo Librandi, Oct 17 2013

CROSSREFS

Column 5 of triangle A094414.

Sequence in context: A137147 A341178 A114914 * A330191 A376291 A363352

Adjacent sequences: A026043 A026044 A026045 * A026047 A026048 A026049

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved