OFFSET
1,2
COMMENTS
Geometrically, the partial sums of A092181 may be interpreted as 5-dimensional icositetrachoronal hyperpyramidal numbers. The icositetrachoron is a convex regular 4-D polytope with Schlaefli symbol {3,4,3}.
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
FORMULA
a(n) = Sum_{k=1..n} A092181(k).
From Colin Barker, Aug 15 2018: (Start)
G.f.: x*(1 + 19*x + 43*x^2 + 9*x^3) / (1 - x)^6.
a(n) = n*(7 - 10*n^2 + 15*n^3 + 18*n^4) / 30.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.
(End)
MATHEMATICA
Table[n*(7 - 10*n^2 + 15*n^3 + 18*n^4)/30, {n, 40}] (* Wesley Ivan Hurt, Oct 30 2022 *)
PROG
(PARI) Vec(x*(1 + 19*x + 43*x^2 + 9*x^3) / (1 - x)^6 + O(x^40)) \\ Colin Barker, Aug 15 2018
(PARI) a(n) = (n*(7 - 10*n^2 + 15*n^3 + 18*n^4)) / 30 \\ Colin Barker, Aug 15 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alejandro J. Becerra Jr., Aug 15 2018
STATUS
approved