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A144390 3*n^2 - n - 1. 8
1, 9, 23, 43, 69, 101, 139, 183, 233, 289, 351, 419, 493, 573, 659, 751, 849, 953, 1063, 1179, 1301, 1429, 1563, 1703, 1849, 2001, 2159, 2323, 2493, 2669, 2851, 3039, 3233, 3433, 3639, 3851, 4069, 4293, 4523, 4759, 5001, 5249, 5503, 5763, 6029, 6301, 6579 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Sequence's original Name was "First bisection of A135370."

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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

FORMULA

a(n+1) = a(n)+6*n+2; see A016933.

a(n) = 3*n^2-n-1. - Paolo P. Lava, Oct 06 2008

G.f.: x*(1+6*x-x^2)/(1-x)^3. a(n) = A049450(n)-1. - R. J. Mathar, Oct 24 2008

a(-n) = A144391(n). - Michael Somos, Mar 27 2014

MAPLE

A144390:=n->3*n^2-n-1; seq(A144390(n), n=1..50); # Wesley Ivan Hurt, Mar 26 2014

MATHEMATICA

s=-1; lst={}; Do[s+=n+1; AppendTo[lst, s], {n, 1, 6!, 6}]; lst (* Vladimir Joseph Stephan Orlovsky, Oct 25 2008 *)

PROG

(MAGMA) [3*n^2-n-1: n in [1..60]]; // Vincenzo Librandi, Jun 14 2011

(PARI) a(n)=3*n^2-n-1 \\ Charles R Greathouse IV, Oct 07 2015

CROSSREFS

Cf. A016933.

Sequence in context: A199714 A054302 A147395 * A024843 A183453 A159221

Adjacent sequences:  A144387 A144388 A144389 * A144391 A144392 A144393

KEYWORD

nonn,easy

AUTHOR

Paul Curtz, Oct 02 2008

EXTENSIONS

Edited by R. J. Mathar, Oct 24 2008

More terms from Vladimir Joseph Stephan Orlovsky, Oct 25 2008

STATUS

approved

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Last modified March 26 05:21 EDT 2017. Contains 284111 sequences.