OFFSET
0,3
COMMENTS
Row sums of centered hexagonal numbers A003215 treated as a regular triangle.
LINKS
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
FORMULA
a(n) = (n^3 + 3*n^5)/4.
G.f.: x*(1 + 20*x + 48*x^2 + 20*x^3 + x^4)/(1 - x)^6. - Stefano Spezia, Sep 19 2022
MATHEMATICA
a[n_] := (n^3 + 3*n^5)/4; Array[a, 35, 0] (* Amiram Eldar, Sep 18 2022 *)
PROG
(PARI) a(n) = n^3*(3*n^2+1)/4 \\ Charles R Greathouse IV, Sep 19 2022
CROSSREFS
Cf. A059827 (cubes of triangular numbers).
KEYWORD
nonn,easy
AUTHOR
Kelvin Voskuijl, Sep 16 2022
STATUS
approved