A164015 5 times centered pentagonal numbers: 5*(5*n^2 + 5*n + 2)/2.

5, 30, 80, 155, 255, 380, 530, 705, 905, 1130, 1380, 1655, 1955, 2280, 2630, 3005, 3405, 3830, 4280, 4755, 5255, 5780, 6330, 6905, 7505, 8130, 8780, 9455, 10155, 10880, 11630, 12405, 13205, 14030, 14880, 15755, 16655, 17580, 18530

Offset

0,1

Links

Ivan Panchenko, Table of n, a(n) for n = 0..1000

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

Formula

a(n) = 5*A005891(n).

a(n) = a(n-1) + 25*n (with a(0)=5). - Vincenzo Librandi, Nov 30 2010

a(0)=5, a(1)=30, a(2)=80, a(n) = 3*a(n-1)-3*a(n-2)+a(n-3). - Harvey P. Dale, Oct 08 2011

G.f.: (5*(x*(x+3)+1))/(1-x)^3. - Harvey P. Dale, Oct 08 2011

E.g.f.: (5/2)*(2 + 10*x + 5*x^2)*exp(x). - G. C. Greubel, Sep 06 2017

Mathematica

Table[5(5n^2+5n+2)/2, {n, 0, 40}] (* or *) LinearRecurrence[{3, -3, 1}, {5, 30, 80}, 40] (* Harvey P. Dale, Oct 08 2011 *)

Prog

(PARI) a(n)=25*n*(n+1)/2+5 \\ Charles R Greathouse IV, Jul 17 2011

Crossrefs

Cf. A005891, A152734, A164013, A108099, A164016.

Sequence in context: A187275 A344070 A273480 * A128302 A258582 A288679

Adjacent sequences: A164012 A164013 A164014 * A164016 A164017 A164018

Keyword

easy,nonn

Author

Omar E. Pol, Nov 07 2009

Status

approved