The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A027470 a(n) = 225*(n-1)*(n-2)/2. 1
 225, 675, 1350, 2250, 3375, 4725, 6300, 8100, 10125, 12375, 14850, 17550, 20475, 23625, 27000, 30600, 34425, 38475, 42750, 47250, 51975, 56925, 62100, 67500, 73125, 78975, 85050, 91350, 97875, 104625, 111600, 118800, 126225 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 3..1000 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA Numerators of sequence a[n,n-2] in (a[i,j])^4 where a[i,j] = binomial(i-1, j-1)/2^(i-1) if j<=i, 0 if j>i. G.f.: 225*(1 - 3*x + 3*x^2)/(1 - x)^3. - Vincenzo Librandi, Dec 29 2012 a(3)=225, a(4)=675, a(5)=1350, a(n) = 3*a(n-1) -3*a(n-2) +a(n-3). - Harvey P. Dale, Feb 01 2013 MAPLE seq(225*binomial(n-1, 2), n=3..50); # G. C. Greubel, May 14 2021 MATHEMATICA Table[225 (n-1) (n-2)/2, {n, 3, 50}] (* Vincenzo Librandi, Dec 29 2012 *) LinearRecurrence[{3, -3, 1}, {225, 675, 1350}, 40] (* Harvey P. Dale, Feb 01 2013 *) PROG (MAGMA) [225*(n-1)*(n-2)/2: n in [3..50]]; // Vincenzo Librandi, Dec 29 2012 (PARI) a(n)=225*(n-1)*(n-2)/2 \\ Charles R Greathouse IV, Jun 17 2017 (Sage) [225*binomial(n-1, 2) for n in (3..50)] # G. C. Greubel, May 14 2021 CROSSREFS Third diagonal of A027467. Sequence in context: A193003 A287298 A117246 * A134934 A250807 A330096 Adjacent sequences:  A027467 A027468 A027469 * A027471 A027472 A027473 KEYWORD nonn,easy AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 23 17:37 EDT 2021. Contains 347618 sequences. (Running on oeis4.)