A168278 (10*n + 5*(-1)^n + 3)/4.

2, 7, 7, 12, 12, 17, 17, 22, 22, 27, 27, 32, 32, 37, 37, 42, 42, 47, 47, 52, 52, 57, 57, 62, 62, 67, 67, 72, 72, 77, 77, 82, 82, 87, 87, 92, 92, 97, 97, 102, 102, 107, 107, 112, 112, 117, 117, 122, 122, 127, 127, 132, 132, 137, 137, 142, 142, 147, 147, 152, 152, 157

Offset: 1

Author

Vincenzo Librandi, Nov 22 2009

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A016873, A168282.

Programs

Magma

[5*n/2+3/4+5*(-1)^n/4: n in [1..70]]; // Vincenzo Librandi, Sep 16 2013

Mathematica

Table[5 n/2 + 3/4 + 5 (-1)^n/4, {n, 70}] (* Bruno Berselli, Sep 16 2013 *)
CoefficientList[Series[- (- 2 - 5 x + 2 x^2) / ((1 + x) (x - 1)^2), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 16 2013 *)

Formula

G.f.: x*(2 + 5*x - 2*x^2)/( (1+x)*(x-1)^2 ). - R. J. Mathar, Jan 05 2011

a(n) = A016873(floor(n/2)). - R. J. Mathar, Jan 05 2011

a(n) = A168282(n) + 1. - Bruno Berselli, Sep 16 2013

E.g.f.: (1/4)*(5 - 8*exp(x) + (3 + 10*x)*exp(2*x))*exp(-x). - G. C. Greubel, Jul 16 2016

Extensions

New definition by R. J. Mathar, Jan 05 2011