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) = (1/6)*n*(109*n^2 - 153*n + 50).
G.f.: x*(1 + 56*x + 52*x^2)/(1-x)^4. - Colin Barker, Jan 19 2012
From Elmo R. Oliveira, Aug 05 2025: (Start)
E.g.f.: exp(x)*x*(109*x^2 + 174*x + 6)/6.
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, 286, 788}, 50] (* Paolo Xausa, Aug 06 2025 *)
PROG
(Magma) [(1/6)*(109*n^3-153*n^2+50*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
