OFFSET
0,2
REFERENCES
A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (7,-15,13,-4)
FORMULA
a(n) = ((2^(2n+7)) - (9*(n^2) + 51n + 74))/54.
a(n) = 4a(n-1) + C(n+2,2); a(0)=1.
a(n) = Sum_{k=0..n, binomial(n+3, k+3)3^k}. - Paul Barry, Aug 20 2004
G.f.: 1/((1-x)^3*(1-4*x)). - Colin Barker, Jan 12 2012
MATHEMATICA
CoefficientList[Series[1/((1-x)^3*(1-4*x)), {x, 0, 25}], x] (* Vincenzo Librandi, Apr 28 2012 *)
PROG
(Magma) [((2^(2*n+7))-(9*(n^2)+51*n+74))/54: n in [0..25]]; // Vincenzo Librandi, Apr 28 2012
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Barry E. Williams, Jan 25 2000
STATUS
approved