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A172075
a(n) = n*(n+1)*(9*n^2 - n - 5)/6.
1
0, 1, 29, 146, 450, 1075, 2191, 4004, 6756, 10725, 16225, 23606, 33254, 45591, 61075, 80200, 103496, 131529, 164901, 204250, 250250, 303611, 365079, 435436, 515500, 606125, 708201, 822654, 950446, 1092575, 1250075, 1424016, 1615504, 1825681
OFFSET
0,3
LINKS
B. Berselli, A description of the recursive method in Formula lines: website Matem@ticamente (in Italian).
FORMULA
G.f.: x*(1 + 24*x + 11*x^2)/(1-x)^5.
a(n) = n*A172073(n)- Sum_{i=0..n-1} A172073(i).
The last formula is the case d=6 in the identity n*(n*(n+1)*(2*d*n -2*d +3)/6) - Sum_{k=0..n-1} k*(k+1)*(2*d*k - 2*d + 3)/6 = n*(n+1)*(3*d*n^2 -d*n + 4*n - 2*d + 2)/12. - Bruno Berselli, Dec 07 2010
E.g.f.: x*(6 + 81*x + 62*x^2 + 9*x^3)*exp(x)/6. - G. C. Greubel, Aug 30 2019
MAPLE
seq(n*(n+1)*(9*n^2 -n -5)/6, n=0..40); # G. C. Greubel, Aug 30 2019
MATHEMATICA
CoefficientList[Series[x(1+24x+11x^2)/(1-x)^5, {x, 0, 40}], x] (* Vincenzo Librandi, Jan 01 2014 *)
LinearRecurrence[{5, -10, 10, -5, 1}, {0, 1, 29, 146, 450}, 40] (* Harvey P. Dale, May 11 2014 *)
PROG
(Magma) [n*(n+1)*(9*n^2-n-5)/6: n in [0..50]]; // Vincenzo Librandi, Jan 01 2014
(PARI) vector(40, n, m=n-1; n*m*(9*m^2 -m -5)/6) \\ G. C. Greubel, Aug 30 2019
(Sage) [n*(n+1)*(9*n^2 -n -5)/6 for n in (0..40)] # G. C. Greubel, Aug 30 2019
(GAP) List([0..40], n-> n*(n+1)*(9*n^2 -n -5)/6); # G. C. Greubel, Aug 30 2019
CROSSREFS
Cf. A172073.
Sequence in context: A123845 A297722 A042642 * A042644 A263126 A221981
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jan 25 2010
STATUS
approved