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A195043 Concentric 11-gonal numbers. 7
0, 1, 11, 23, 44, 67, 99, 133, 176, 221, 275, 331, 396, 463, 539, 617, 704, 793, 891, 991, 1100, 1211, 1331, 1453, 1584, 1717, 1859, 2003, 2156, 2311, 2475, 2641, 2816, 2993, 3179, 3367, 3564, 3763, 3971, 4181, 4400, 4621, 4851, 5083, 5324, 5567 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Also concentric hendecagonal numbers. A033584 and A069173 interleaved.

Partial sums of A175885. [Reinhard Zumkeller, Jan 07 2012]

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Index entries for linear recurrences with constant coefficients, signature (2,0,-2,1).

FORMULA

a(n) = 11*n^2/4+7*((-1)^n-1)/8.

a(n) = -a(n-1)+A069125(n). - Vincenzo Librandi, Sep 30 2011

a(n) = 2*a(n-1)-2*a(n-3)+a(n-4). G.f.: -x*(x^2+9*x+1) / ((x-1)^3*(x+1)). - Colin Barker, Sep 15 2013

PROG

(MAGMA) [11*n^2/4+7*((-1)^n-1)/8: n in [0..50]]; // Vincenzo Librandi, Sep 30 2011

(Haskell)

a195043 n = a195043_list !! n

a195043_list = scanl (+) 0 a175885_list

-- Reinhard Zumkeller, Jan 07 2012

(PARI) Vec(-x*(x^2+9*x+1)/((x-1)^3*(x+1)) + O(x^100)) \\ Colin Barker, Sep 15 2013

CROSSREFS

Column 11 of A195040.

Cf. A032527, A032528, A195042, A195142, A195143, A195045.

Sequence in context: A228444 A191235 A146451 * A029468 A198588 A068231

Adjacent sequences:  A195040 A195041 A195042 * A195044 A195045 A195046

KEYWORD

nonn,easy,changed

AUTHOR

Omar E. Pol, Sep 27 2011

STATUS

approved

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Last modified June 24 09:56 EDT 2017. Contains 288697 sequences.