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A027694 a(n) = n^2 + n + 9. 5
9, 11, 15, 21, 29, 39, 51, 65, 81, 99, 119, 141, 165, 191, 219, 249, 281, 315, 351, 389, 429, 471, 515, 561, 609, 659, 711, 765, 821, 879, 939, 1001, 1065, 1131, 1199, 1269, 1341, 1415, 1491, 1569, 1649, 1731, 1815, 1901, 1989, 2079, 2171 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

For n > 3, a(n) = A176271(n+1,5). - Reinhard Zumkeller, Apr 13 2010

LINKS

Table of n, a(n) for n=0..46.

P. De Geest, Palindromic Quasi_Over_Squares of the form n^2+(n+X)

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

FORMULA

G.f.: (-9 + 16*x - 9*x^2) / (x-1)^3. - R. J. Mathar, Feb 07 2011

a(0) = 9, a(n) = a(n - 1) + 2n. - Vincenzo Librandi, Feb 07 2011

MAPLE

with (combinat):seq(fibonacci(3, n)+n+8, n=0..46); # Zerinvary Lajos, Jun 07 2008

MATHEMATICA

Table[n^2+n+9, {n, 0, 50}]  (* Harvey P. Dale, Feb 07 2011 *)

PROG

(PARI) a(n)=n^2+n+9 \\ Charles R Greathouse IV, Oct 07 2015

CROSSREFS

Cf. A002522.

Sequence in context: A287340 A037009 A163096 * A063191 A329167 A216976

Adjacent sequences:  A027691 A027692 A027693 * A027695 A027696 A027697

KEYWORD

nonn,easy

AUTHOR

Patrick De Geest

STATUS

approved

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Last modified November 12 09:01 EST 2019. Contains 329052 sequences. (Running on oeis4.)