OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Stefano Spezia, Illustration for n = 3.
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = n*(10*n^2+9*n+1)/2.
From Colin Barker, Dec 02 2014: (Start)
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 3.
G.f.: x*(x^2+19*x+10) / (x-1)^4. (End)
E.g.f.: exp(x)*x*(20 + 39*x + 10*x^2)/2. - Stefano Spezia, Sep 18 2024
MATHEMATICA
LinearRecurrence[{4, -6, 4, -1}, {0, 10, 59, 177}, 50] (* Paolo Xausa, Sep 18 2024 *)
PROG
(PARI) concat(0, Vec(x*(x^2+19*x+10)/(x-1)^4 + O(x^100))) \\ Colin Barker, Dec 02 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Name clarified by Paolo Xausa, Sep 19 2024
STATUS
approved