A186030 a(n) = n*(13*n-3)/2.

0, 5, 23, 54, 98, 155, 225, 308, 404, 513, 635, 770, 918, 1079, 1253, 1440, 1640, 1853, 2079, 2318, 2570, 2835, 3113, 3404, 3708, 4025, 4355, 4698, 5054, 5423, 5805, 6200, 6608, 7029, 7463, 7910, 8370, 8843, 9329, 9828, 10340, 10865, 11403

Offset: 0

Author

Bruno Berselli, Feb 11 2011

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Crossrefs

Cf. numbers of the form n*(d*n+10-d)/2 indexed in A140090.

Cf. A154609 (first differences).

Cf. A008585, A152742.

Programs

Magma

[ n*(13*n-3)/2 : n in [0..42] ];

Mathematica

Table[n (13n-3)/2,{n,0,60}]  (* Harvey P. Dale, Feb 24 2011 *)

PARI

a(n)=n*(13*n-3)/2 \\ Charles R Greathouse IV, Oct 07 2015

Formula

G.f.: x*(5+8*x)/(1-x)^3.

From Bruno Berselli, Sep 05 2011: (Start)

a(n) - a(-n) = -A008585(n).

a(n) + a(-n) = A152742(n). (End)

E.g.f.: (1/2)*(13*x^2 + 10*x)*exp(x). - G. C. Greubel, Jul 17 2017