OFFSET
0,6
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
E. Czabarka et al, Enumerations of peaks and valleys on non-decreasing Dyck paths, Disc. Math. 341 (2018) 2789-2807.
Index entries for linear recurrences with constant coefficients, signature (9,-31,50,-36,8).
FORMULA
a(n) = 9*a(n-1) - 31*a(n-2) + 50*a(n-3) - 36*a(n-4) + 8*a(n-5) for n>9. - Colin Barker, Apr 11 2019
MAPLE
(1-x)^2*x^4*(1+x-8*x^2+7*x^3)/(1-2*x)^3/(1-3*x+x^2) ;
taylor(%, x=0, 30) ;
gfun[seriestolist](%) ; # R. J. Mathar, Nov 25 2018
MATHEMATICA
LinearRecurrence[{9, -31, 50, -36, 8}, {0, 0, 0, 0, 1, 8, 32, 114, 376, 1177}, 30] (* Harvey P. Dale, Nov 03 2019 *)
PROG
(PARI) concat([0, 0, 0, 0], Vec(x^4*(1 - x)^2*(1 + x - 8*x^2 + 7*x^3) / ((1 - 2*x)^3*(1 - 3*x + x^2)) + O(x^40))) \\ Colin Barker, Apr 11 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Sep 18 2018
STATUS
approved