OFFSET
0,3
COMMENTS
Values divided by 2 are 0, 0, 1, 3, 9, 29, 97, 329, 1121, 3825, 13057, ...
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
László Németh, Pascal pyramid in the space H^2 x R, arXiv:1701.06022 [math.CO], 2017 (1st line of Table 2).
Index entries for linear recurrences with constant coefficients, signature (5,-6,2).
FORMULA
a(n) = 5*a(n-1) - 6*a(n-2) + 2*a(n-3), n >= 3.
From Colin Barker, Oct 07 2017: (Start)
G.f.: 2*x^2*(1 - 2*x) / ((1 - x)*(1 - 4*x + 2*x^2)).
a(n) = (4 + (2+sqrt(2))^n*(-4+3*sqrt(2)) - (2-sqrt(2))^n*(4+3*sqrt(2))) / 2 for n>0.
(End)
MATHEMATICA
LinearRecurrence[{5, -6, 2}, {0, 0, 2, 6}, 30] (* Harvey P. Dale, May 24 2019 *)
PROG
(PARI) concat(vector(2), Vec(2*x^2*(1 - 2*x) / ((1 - x)*(1 - 4*x + 2*x^2)) + O(x^30))) \\ Colin Barker, Oct 07 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric M. Schmidt, Sep 30 2017
STATUS
approved