OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..5000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = (1/2)*n*(35*n^2 - 47*n + 14).
G.f.: x*(1 + 56*x + 48*x^2)/(1-x)^4. - Colin Barker, Feb 12 2012
From Elmo R. Oliveira, Aug 05 2025: (Start)
E.g.f.: exp(x)*x*(35*x^2 + 58*x + 2)/2.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 4. (End)
MATHEMATICA
LinearRecurrence[{4, -6, 4, -1}, {1, 60, 282, 772}, 50] (* Paolo Xausa, Aug 06 2025 *)
PROG
(Magma) [(1/6)*(105*n^3-141*n^2+42*n): n in [1..40]]; // Vincenzo Librandi, Jul 19 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
James A. Record (james.record(AT)gmail.com), Nov 07 2004
STATUS
approved