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 A161708 a(n) = -n^3 + 7*n^2 - 5*n + 1. 20
 1, 2, 11, 22, 29, 26, 7, -34, -103, -206, -349, -538, -779, -1078, -1441, -1874, -2383, -2974, -3653, -4426, -5299, -6278, -7369, -8578, -9911, -11374, -12973, -14714, -16603, -18646, -20849, -23218, -25759, -28478, -31381, -34474, -37763, -41254 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS {a(k): 0 <= k < 4} = divisors of 22: a(n) = A027750(A006218(21) + k + 1), 0 <= k < A000005(22). LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..10000 Reinhard Zumkeller, Enumerations of Divisors Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA a(n) = C(n,0) + C(n,1) + 8*C(n,2) - 6*C(n,3). G.f.: -(-1+2*x-9*x^2+14*x^3)/(-1+x)^4. - R. J. Mathar, Jun 18 2009 a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4) with a(0)=1, a(1)=2, a(2)=11, a(3)=22. - Harvey P. Dale, Nov 12 2013 E.g.f.: (-x^3 + 4*x^2 + x + 1)*exp(x). - G. C. Greubel, Jul 16 2017 EXAMPLE Differences of divisors of 22 to compute the coefficients of their interpolating polynomial, see formula: 1 2 11 22 1 9 11 8 2 -6 MATHEMATICA Table[-n^3+7n^2-5n+1, {n, 0, 40}] (* or *) LinearRecurrence[{4, -6, 4, -1}, {1, 2, 11, 22}, 40] (* Harvey P. Dale, Nov 12 2013 *) PROG (Magma) [-n^3 + 7*n^2 - 5*n + 1: n in [0..40]]; // Vincenzo Librandi, Jul 17 2011 (PARI) a(n)=-n^3+7*n^2-5*n+1 \\ Charles R Greathouse IV, Sep 24 2015 CROSSREFS Cf. A005408, A000124, A016813, A086514, A000125, A058331, A002522, A161701, A161702, A161703, A000127, A161704, A161706, A161707, A161710, A080856, A161711, A161712, A161713, A161715, A006261. Sequence in context: A218340 A018491 A031010 * A076206 A018563 A018590 Adjacent sequences: A161705 A161706 A161707 * A161709 A161710 A161711 KEYWORD sign,easy AUTHOR Reinhard Zumkeller, Jun 17 2009 STATUS approved

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Last modified April 13 17:26 EDT 2024. Contains 371644 sequences. (Running on oeis4.)