login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A088942 a(n)=60*sum(1<=i<=j<=k<=n,i^2*j/k). 4
0, 60, 390, 1450, 4045, 9421, 19361, 36281, 63326, 104466, 164592, 249612, 366547, 523627, 730387, 997763, 1338188, 1765688, 2295978, 2946558, 3736809, 4688089, 5823829, 7169629, 8753354, 10605230, 12757940, 15246720, 18109455, 21386775 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Always an integer. Can be expressed as a polynomial with rational coefficients of degree 5.

LINKS

Table of n, a(n) for n=0..29.

Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).

FORMULA

a(n) = n/120 * (96n^4 + 765n^3 + 2210n^2 + 2275n + 1354).

G.f.: x*(x^4-5*x^3+10*x^2+30*x+60) / (x-1)^6. - Colin Barker, Jun 15 2013

PROG

(PARI) a(n)=60*sum(k=1, n, sum(j=1, k, sum(i=1, j, i^2*j/k)))

CROSSREFS

Cf. A088941, A088943.

Sequence in context: A056428 A056419 A060489 * A135037 A020868 A223461

Adjacent sequences:  A088939 A088940 A088941 * A088943 A088944 A088945

KEYWORD

nonn,easy

AUTHOR

Benoit Cloitre, Oct 25 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 11 18:50 EST 2019. Contains 329031 sequences. (Running on oeis4.)