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A088945
a(n) =60*sum(1<=u<=v<=w<=m,u^2*v^2/w).
1
0, 60, 690, 3630, 13035, 37059, 89839, 193879, 382834, 704694, 1225368, 2032668, 3240693, 4994613, 7475853, 10907677, 15561172, 21761632, 29895342, 40416762, 53856111, 70827351, 92036571, 118290771, 150507046, 189722170, 237102580
OFFSET
0,2
COMMENTS
Always an integer. Can be expressed as a polynomial with rational coefficients of degree 6.
FORMULA
n*(200*n^5+1752*n^4+5705*n^3+8370*n^2+5075*n+498)/360. - Vladeta Jovovic, Oct 27 2003
G.f.: -x*(x^5-6*x^4+15*x^3+60*x^2+270*x+60) / (x-1)^7. - Colin Barker, Jun 19 2013
MATHEMATICA
LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {0, 60, 690, 3630, 13035, 37059, 89839}, 30] (* Harvey P. Dale, Mar 20 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Benoit Cloitre, Oct 25 2003
STATUS
approved