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 A115565 a(n) = 5*n^4 - 10*n^3 + 20*n^2 - 15*n + 11. 1
 11, 61, 281, 911, 2311, 4961, 9461, 16531, 27011, 41861, 62161, 89111, 124031, 168361, 223661, 291611, 374011, 472781, 589961, 727711, 888311, 1074161, 1287781, 1531811, 1809011, 2122261, 2474561, 2869031, 3308911, 3797561, 4338461, 4935211, 5591531 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..10000 Index entries for linear recurrences with constant coefficients, signature (5, -10, 10, -5, 1). FORMULA a(1-n) = a(n) = 5*(n^2-n)^2 +15*(n^2-n) +11. - Michael Somos, May 15 2006 a(1)=11, a(2)=61, a(3)=281, a(4)=911, a(5)=2311, a(n)=5*a(n-1)-10*a(n-2)+ 10*a(n-3)-5*a(n-4)+a(n-5). - Harvey P. Dale, Oct 03 2011 G.f.: x*(11+6*x+86*x^2+6*x^3+11*x^4)/(1-x)^5. - Wesley Ivan Hurt, Aug 22 2015 MAPLE A115565:=n->5*n^4 - 10*n^3 + 20*n^2 - 15*n + 11: seq(A115565(n), n=1..40); # Wesley Ivan Hurt, Aug 22 2015 MATHEMATICA Table[5n^4-10n^3+20n^2-15n+11, {n, 40}] (* or *) LinearRecurrence[ {5, -10, 10, -5, 1}, {11, 61, 281, 911, 2311}, 40] (* Harvey P. Dale, Oct 03 2011 *) CoefficientList[Series[(11 + 6 x + 86 x^2 + 6 x^3 + 11 x^4)/(1 - x)^5, {x, 0, 40}], x] (* Wesley Ivan Hurt, Aug 22 2015 *) PROG ay1[1] := 11; a[1] :=50; b[1] :=170; c[1] :=240; k := 120; Repeat ay1[1] := ay1[1] + a[1]; a[1] := a[1] + b[1]; b[1] := b[1] + c[1]; c[1] := c[1] + k; writeln(ay1[1]); Until 1 < 0; (Magma) [5*(n^2-n)^2 +15*(n^2-n) +11: n in [1..40]]; // Vincenzo Librandi, Oct 04 2011 (PARI) a(n) = 5*n^4 - 10*n^3 + 20*n^2 - 15*n + 11 \\ Charles R Greathouse IV, Aug 22 2015 (PARI) first(m)=vector(m, i, 5*i^4 - 10*i^3 + 20*i^2 - 15*i + 11) \\ Anders Hellström, Aug 22 2015 CROSSREFS Sequence in context: A023298 A320145 A106992 * A137410 A268863 A199414 Adjacent sequences: A115562 A115563 A115564 * A115566 A115567 A115568 KEYWORD nonn,easy AUTHOR Aldrich Stevens (Aldrichstevens(AT)msn.com), Mar 11 2006 EXTENSIONS Checked by N. J. A. Sloane, Mar 29 2006 Edited by N. J. A. Sloane, Jun 13 2008 STATUS approved

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Last modified February 28 08:11 EST 2024. Contains 370393 sequences. (Running on oeis4.)