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A155966 a(n) = 2*n^2 + 8. 4
8, 10, 16, 26, 40, 58, 80, 106, 136, 170, 208, 250, 296, 346, 400, 458, 520, 586, 656, 730, 808, 890, 976, 1066, 1160, 1258, 1360, 1466, 1576, 1690, 1808, 1930, 2056, 2186, 2320, 2458, 2600, 2746, 2896, 3050, 3208, 3370, 3536, 3706, 3880, 4058 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

The identity (n^3+4*n)^2 + (2*n^2+8)^2 = (n^2+4)^3 can be written as A155965(n)^2 + a(n)^2 = A087475(n)^3.

LINKS

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

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

FORMULA

G.f.: 2*(4 - 7*x + 5*x^2)/(1 - x)^3.

a(n) = a(-n) = 3*a(n-1) - 3*a(n-2) + a(n-3).

a(n) = 2*A087475(n). [Bruno Berselli, Mar 13 2015]

MATHEMATICA

LinearRecurrence[{3, -3, 1}, {8, 10, 16}, 50] (* Vincenzo Librandi, Feb 22 2012

2*Range[0, 50]^2+8 (* Harvey P. Dale, Mar 01 2018 *)

PROG

(PARI) a(n)=2*n^2+8 \\ Charles R Greathouse IV, Jan 11 2012

(MAGMA) [2*n^2+8: n in [0..50]]; // Vincenzo Librandi, Feb 22 2012

CROSSREFS

Cf. A087475.

Cf. similar sequences listed in A255843.

Sequence in context: A058633 A165143 A289687 * A228072 A038209 A319293

Adjacent sequences:  A155963 A155964 A155965 * A155967 A155968 A155969

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Jan 31 2009

EXTENSIONS

Offset changed from 1 to 0 and added a(0)=8 by Bruno Berselli, Mar 13 2015

STATUS

approved

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Last modified May 17 21:11 EDT 2021. Contains 343990 sequences. (Running on oeis4.)