A022273 a(n) = n*(15*n + 1)/2.

0, 8, 31, 69, 122, 190, 273, 371, 484, 612, 755, 913, 1086, 1274, 1477, 1695, 1928, 2176, 2439, 2717, 3010, 3318, 3641, 3979, 4332, 4700, 5083, 5481, 5894, 6322, 6765, 7223, 7696, 8184, 8687, 9205, 9738, 10286, 10849, 11427, 12020, 12628, 13251, 13889

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..5000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Formula

a(n) = A110449(n, 7) for n>6.

a(n) = 15*n + a(n-1) - 7 for n>0, a(0)=0. - Vincenzo Librandi, Aug 04 2010

G.f.: x*(8+7*x)/(1-x)^3. - Vincenzo Librandi, Mar 31 2015

a(n) = 3*a(n-1) - 3*a(n-2) - a(n-3) for n>2. - Vincenzo Librandi, Mar 31 2015

a(n) = A022272(-n). - Bruno Berselli, Mar 31 2015

a(n) + a(-n) = A064761(n). - Bruno Berselli, Mar 31 2015

a(n) = A000217(8*n) - A000217(7*n). - Bruno Berselli, Oct 13 2016

E.g.f.: (x/2)*(15*x + 16)*exp(x). - G. C. Greubel, Aug 23 2017

Mathematica

Table[n (15 n + 1)/2, {n, 0, 40}] (* Bruno Berselli, Mar 12 2015 *)
CoefficientList[Series[x (8 + 7 x) / (1 - x)^3, {x, 0, 40}], x]; (* Vincenzo Librandi, Mar 31 2015 *)

Prog

(Magma) [n*(15*n + 1)/2: n in [0..45]]; // Vincenzo Librandi, Mar 31 2015
(PARI) a(n)=n*(15*n+1)/2 \\ Charles R Greathouse IV, Jun 17 2017

Crossrefs

Cf. A022272, A064761, A110449.

Cf. similar sequences listed in A022289.

Sequence in context: A067950 A303037 A230386 * A302874 A061294 A240707

Adjacent sequences: A022270 A022271 A022272 * A022274 A022275 A022276

Keyword

nonn,easy

Author

N. J. A. Sloane

Extensions

More terms from Vincenzo Librandi, Mar 31 2015

Status

approved