OFFSET
1,3
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (50,-916,7914,-34047,70740,-56700).
FORMULA
a(n) = A334774(n,3)/3. - Andrew Howroyd, May 12 2020
From Colin Barker, Jul 18 2020: (Start)
G.f.: x^3*(8 + 83*x - 617*x^2 - 1056*x^3) / ((1 - 3*x)^3*(1 - 10*x)^2*(1 - 21*x)).
a(n) = 50*a(n-1) - 916*a(n-2) + 7914*a(n-3) - 34047*a(n-4) + 70740*a(n-5) - 56700*a(n-6) for n>6.
(End)
PROG
(PARI) \\ PeaksBySig defined in A334774.
a(n) = {PeaksBySig(vector(n, i, 2), [2])[1]/3} \\ Andrew Howroyd, May 12 2020
(PARI) concat([0, 0], Vec(x^3*(8 + 83*x - 617*x^2 - 1056*x^3) / ((1 - 3*x)^3*(1 - 10*x)^2*(1 - 21*x)) + O(x^22))) \\ Colin Barker, Jul 18 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Dec 06 2008
EXTENSIONS
Terms a(12) and beyond from Andrew Howroyd, May 11 2020
STATUS
approved