This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A180232 n*(17*n-13)/2. 3
 0, 2, 21, 57, 110, 180, 267, 371, 492, 630, 785, 957, 1146, 1352, 1575, 1815, 2072, 2346, 2637, 2945, 3270, 3612, 3971, 4347, 4740, 5150, 5577, 6021, 6482, 6960, 7455, 7967, 8496, 9042, 9605, 10185, 10782, 11396, 12027, 12675, 13340, 14022, 14721, 15437, 16170 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..10000 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = n+A051871(n). a(n) = 3*a(n-1)-3*a(n-2)+a(n-3). G.f.: x*(2+15*x) / (1-x)^3. MATHEMATICA Table[(n(17n-13))/2, {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 2, 21}, 50] (* Harvey P. Dale, Sep 14 2011 *) PROG (PARI) a(n)=1/2*(17*n^2 - 13*n); (MAGMA) [n*(17*n-13)/2:n in [0..40]]; // Vincenzo Librandi, Sep 15 2011 CROSSREFS Cf. A051871. Cf. A226488. [Bruno Berselli, Jun 10 2013] Sequence in context: A074875 A231807 A097718 * A075681 A212257 A034520 Adjacent sequences:  A180229 A180230 A180231 * A180233 A180234 A180235 KEYWORD nonn,easy AUTHOR Graziano Aglietti (mg5055(AT)mclink.it), Aug 18 2010 EXTENSIONS More terms and g.f. from R. J. Mathar, Aug 29 2010 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.