This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A022288 #32 Aug 24 2017 16:35:02 %S A022288 0,15,61,138,246,385,555,756,988,1251,1545,1870,2226,2613,3031,3480, %T A022288 3960,4471,5013,5586,6190,6825,7491,8188,8916,9675,10465,11286,12138, %U A022288 13021,13935,14880,15856,16863,17901 %N A022288 a(n) = n*(31*n-1)/2. %H A022288 Harvey P. Dale, <a href="/A022288/b022288.txt">Table of n, a(n) for n = 0..1000</a> %H A022288 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1). %F A022288 a(n) = 31*n + a(n-1) - 16 for n>0, a(0)=0. - _Vincenzo Librandi_, Aug 04 2010 %F A022288 a(0)=0, a(1)=15, a(2)=61; for n>2, a(n) = 3*a(n-1)-3*a(n-2)+a(n-3). - _Harvey P. Dale_, Mar 31 2014 %F A022288 G.f.: x*(15 + 16*x)/(1 - x)^3. - _R. J. Mathar_, Sep 02 2016 %F A022288 a(n) = A000217(16*n-1) - A000217(15*n-1). In general, n*((2*k+1)*n - 1)/2 = A000217((k+1)*n-1) - A000217(k*n-1), and the ordinary generating function is x*(k + (k+1)*x)/(1 - x)^3. - _Bruno Berselli_, Oct 14 2016 %F A022288 E.g.f.: (x/2)*(31*x + 30)*exp(x). - _G. C. Greubel_, Aug 24 2017 %t A022288 Table[n (31 n - 1)/2, {n, 0, 40}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 15, 61}, 40] (* _Harvey P. Dale_, Mar 31 2014 *) %o A022288 (PARI) a(n)=n*(31*n-1)/2 \\ _Charles R Greathouse IV_, Jun 17 2017 %Y A022288 Cf. A000217, A022289. %Y A022288 Cf. similar sequences of the form n*((2*k+1)*n - 1)/2: A161680 (k=0), A000326 (k=1), A005476 (k=2), A022264 (k=3), A022266 (k=4), A022268 (k=5), A022270 (k=6), A022272 (k=7), A022274 (k=8), A022276 (k=9), A022278 (k=10), A022280 (k=11), A022282 (k=12), A022284 (k=13), A022286 (k=14), this sequence (k=15). %K A022288 nonn,easy %O A022288 0,2 %A A022288 _N. J. A. Sloane_