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A239449 7*n^2 - 5*n + 1. 3
1, 3, 19, 49, 93, 151, 223, 309, 409, 523, 651, 793, 949, 1119, 1303, 1501, 1713, 1939, 2179, 2433, 2701, 2983, 3279, 3589, 3913, 4251, 4603, 4969, 5349, 5743, 6151, 6573, 7009, 7459, 7923, 8401, 8893, 9399, 9919, 10453, 11001, 11563, 12139, 12729, 13333 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n) = A239426(n) / A003215(n-1).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

G.f.: ( -1-13*x^2 ) / (x-1)^3 . - R. J. Mathar, Mar 31 2014

MATHEMATICA

CoefficientList[Series[(1 + 13 x^2)/(1 - x)^3, {x, 0, 50}], x] (* Vincenzo Librandi, Apr 02 2014 *)

PROG

(Haskell)

a239449 n = (7 * n - 5) * n + 1

(MAGMA) [7*n^2-5*n+1: n in [0..50]]; // Vincenzo Librandi, Apr 02 2014

(PARI) a(n)=7*n^2-5*n+1 \\ Charles R Greathouse IV, Jun 17 2017

CROSSREFS

Sequence in context: A023280 A054697 A214883 * A112627 A222185 A265774

Adjacent sequences:  A239446 A239447 A239448 * A239450 A239451 A239452

KEYWORD

nonn,easy

AUTHOR

Reinhard Zumkeller, Mar 19 2014

STATUS

approved

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Last modified September 20 16:14 EDT 2017. Contains 292276 sequences.