OFFSET
0,2
REFERENCES
Jolley, Summation of Series, Dover (1961).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).
FORMULA
Sum_{n>=1} 1/a(n) = Pi^2/4-39/16 = 0.029901100272... [Jolley eq 241]
G.f.: 36*x*(1+x)*(1 +8*x +x^2)/(1-x)^7 . - R. J. Mathar, Oct 03 2011
a(n) = (Sum_{k=0..n} (2*k+1))^3 - Sum_{k=0..n} (2*k+1)^3. - Philippe Deléham, Mar 10 2014
E.g.f.: exp(x)*x*(36+252*x+330*x^2+138*x^3+21*x^4+x^5). - Stefano Spezia, Sep 04 2019
Sum_{n>=1} (-1)^(n+1)/a(n) = Pi^2/24 - 7/16. - Amiram Eldar, Jul 02 2020
EXAMPLE
a(0) = 1^3 - 1^3 = 0;
a(1) = (1+3)^3 - (1^3+3^3) = 64 - 28 = 36;
a(2) = (1+3+5)^3 - (1^3+3^3+5^3) = 729 - 153 = 576;
a(3) = (1+3+5+7)^3 - (1^3+3^3+5^3+7^3) = 4096 - 496 = 3600;
a(4) = (1+3+5+7+9)^3 - (1^3+3^3+5^3+7^3+9^3) = 15625 - 1225 = 14400; etc. - Philippe Deléham, Mar 10 2014
MAPLE
MATHEMATICA
Table[n^2*(n+1)^2*(n+2)^2, {n, 0, 30}] (* Vladimir Joseph Stephan Orlovsky, Apr 19 2011 *)
Times@@@Partition[Range[0, 30]^2, 3, 1] (* Harvey P. Dale, Sep 02 2016 *)
PROG
(Magma) [n^2*(n+1)^2*(n+2)^2: n in [0..30]]; // Vincenzo Librandi, Oct 04 2011
(PARI) vector(30, n, (n*(n^2-1))^2) \\ G. C. Greubel, Sep 03 2019
(Sage) [(n*(n^2-1))^2 for n in (1..30)] # G. C. Greubel, Sep 03 2019
(GAP) List([1..30], n-> (n*(n^2-1))^2); # G. C. Greubel, Sep 03 2019
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Kari Lajunen (Kari.Lajunen(AT)Welho.com), Nov 11 2004
STATUS
approved