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!)
 A259415 Triangular numbers (A000217) that are the sum of seventeen consecutive triangular numbers. 6

%I

%S 1326,9180,24531,1979055,5325216,39529386,106368405,8616365901,

%T 23185550130,172110498456,463127571831,37515654714891,100949879501796,

%U 749369070309030,2016457340944761,163343152011830505,439535752164830646,3262752760014579156

%N Triangular numbers (A000217) that are the sum of seventeen consecutive triangular numbers.

%H Colin Barker, <a href="/A259415/b259415.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,4354,-4354,0,0,-1,1).

%F G.f.: -51*x*(11*x^8 +15*x^6 +154*x^5 -47593*x^4 +38324*x^3 +301*x^2 +154*x +26) / ((x -1)*(x^2 -8*x -1)*(x^2 +8*x -1)*(x^4 +66*x^2 +1)).

%e 1326 is in the sequence because T(51) = 1326 = 6 + 10 + 15 + 21 + 28 + 36 + 45 + 55 + 66 + 78 + 91 + 105 + 120 + 136 + 153 + 171 + 190 = T(3) + ... + T(19).

%t LinearRecurrence[{1, 0, 0, 4354, -4354, 0, 0, -1, 1}, {1326, 9180, 24531, 1979055, 5325216, 39529386, 106368405, 8616365901, 23185550130}, 30] (* _Vincenzo Librandi_, Jun 27 2015 *)

%o (PARI) Vec(-51*x*(11*x^8 +15*x^6 +154*x^5 -47593*x^4 +38324*x^3 +301*x^2 +154*x +26) / ((x -1)*(x^2 -8*x -1)*(x^2 +8*x -1)*(x^4 +66*x^2 +1)) + O(x^30))

%Y Cf. A000217, A001110, A129803, A131557, A257711, A257712, A257713, A259413, A259414.

%K nonn,easy

%O 1,1

%A _Colin Barker_, Jun 26 2015

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 April 12 21:13 EDT 2021. Contains 342932 sequences. (Running on oeis4.)