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A117951 a(n) = n^2 + 5. 12
5, 6, 9, 14, 21, 30, 41, 54, 69, 86, 105, 126, 149, 174, 201, 230, 261, 294, 329, 366, 405, 446, 489, 534, 581, 630, 681, 734, 789, 846, 905, 966, 1029, 1094, 1161, 1230, 1301, 1374, 1449, 1526, 1605, 1686, 1769, 1854, 1941, 2030, 2121, 2214, 2309, 2406, 2505 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Ivan Panchenko, Table of n, a(n) for n = 0..1000

Eric Weisstein's World of Mathematics, Near-Square Prime

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

FORMULA

a(n) = 2*n + a(n-1) - 1 (with a(0)=5). - Vincenzo Librandi, Nov 13 2010

From Colin Barker, Apr 10 2012: (Start)

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

G.f.: (5-9*x+6*x^2)/(1-x)^3. (End)

MATHEMATICA

lst={}; Do[AppendTo[lst, n^2+5], {n, 0, 6!, 1}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 07 2008 *)

PROG

(sage) [lucas_number1(3, n, -5) for n in xrange(0, 51)] # Zerinvary Lajos, May 16 2009

(PARI) a(n)=n^2+5 \\ Charles R Greathouse IV, Apr 10 2012

CROSSREFS

For numbers n such that n^2 + 5 is prime, see A078402.

Sequence in context: A218735 A301658 A286338 * A227611 A124519 A154311

Adjacent sequences:  A117948 A117949 A117950 * A117952 A117953 A117954

KEYWORD

nonn,easy

AUTHOR

Eric W. Weisstein, Apr 04 2006

STATUS

approved

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Last modified May 22 05:44 EDT 2018. Contains 304405 sequences. (Running on oeis4.)