OFFSET
0,3
REFERENCES
rec.puzzles Dec 10 1995.
LINKS
Matthew House, Table of n, a(n) for n = 0..1491
Index entries for linear recurrences with constant coefficients, signature (6,-6,-4,16,-16,7).
FORMULA
G.f.: (-7*x^6+15*x^5-12*x^4+2*x^3+4*x^2-5*x+1)/[(1-x+x^2)*(1-5*x+9*x^3-7*x^4)].
MATHEMATICA
Join[{1}, LinearRecurrence[{6, -6, -4, 16, -16, 7}, {1, 4, 16, 72, 335, 1562}, 25]] (* Vincenzo Librandi, Sep 18 2018 *)
PROG
(PARI) Vec((-7*x^6+15*x^5-12*x^4+2*x^3+4*x^2-5*x+1)/((1-x+x^2)*(1-5*x+9*x^3-7*x^4)) + O(x^30)) \\ Michel Marcus, Sep 18 2018
(Magma) I:=[1, 1, 4, 16, 72, 335, 1562]; [n le 7 select I[n] else 6*Self(n-1) - 6*Self(n-2) - 4*Self(n-3) + 16*Self(n-4) - 16*Self(n-5) + 7*Self(n-6): n in [1..30]]; // Vincenzo Librandi, Sep 18 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Matthew House, Dec 24 2016
STATUS
approved