A129026 - OEIS

A129026

a(n) = (1/2)*(n^4 + 11*n^3 + 53*n^2 + 97*n + 54).

0, 27, 108, 282, 600, 1125, 1932, 3108, 4752, 6975, 9900, 13662, 18408, 24297, 31500, 40200, 50592, 62883, 77292, 94050, 113400, 135597, 160908, 189612, 222000, 258375, 299052, 344358, 394632, 450225, 511500, 578832, 652608, 733227, 821100, 916650

(list; graph; refs; listen; history; text; internal format)

OFFSET

-1,2

REFERENCES

Gordon G. Cash and Jerry Ray Dias, Computation, Properties and Resonance Topology of Benzenoid Monoradicals and Polyradicals and the Eigenvectors Belonging to Their Zero Eigenvalues, J. Math. Chem., 30 (2001), 429-444. [See Fig. 2.]

LINKS

Vincenzo Librandi, Table of n, a(n) for n = -1..10000

Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

FORMULA

a(n) = (n+1)*(n+2)*(n^2 + 8*n + 27)/2 = A000217(n+1)*A189836(n+4). - Bruno Berselli, Sep 25 2011

G.f.: -3*(4*x^2 - 9*x + 9) / (x-1)^5. - Colin Barker, Jul 27 2013

MATHEMATICA

Table[(n^4+11n^3+53n^2+97n+54)/2, {n, -1, 40}] (* Harvey P. Dale, Sep 24 2011 *)

PROG

(Magma) [(1/2)*(n^4+11*n^3+53*n^2+97*n+54): n in [-1..40]]; // Vincenzo Librandi, Sep 25 2011

CROSSREFS

Sequence in context: A044659 A244634 A134171 * A042426 A042424 A248095

Adjacent sequences: A129023 A129024 A129025 * A129027 A129028 A129029

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, May 10 2007

STATUS

approved