A131405 Row sums of triangle A131404.
1, 2, 7, 16, 37, 82, 179, 384, 813, 1702, 3531, 7272, 14889, 30342, 61603, 124700, 251825, 507582, 1021535, 2053388, 4123481, 8274002, 16591767, 33254356, 66623317, 133432082, 267164239, 534814024, 1070413693, 2142098602, 4286254091, 8575836312, 17157057669
Offset: 0
Keywords
Examples
a(4) = 37 = sum of row 4 terms of triangle A131404: (1 + 11 + 13 + 11 + 1).
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..500
- Index entries for linear recurrences with constant coefficients, signature (5, -8, 3, 3, -2)
Programs
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PARI
Vec((1 - 3*x + 5*x^2 - 6*x^3 + 4*x^4)/((1 - x)^2*(1 - 2*x)*(1 - x - x^2)) + O(x^40)) \\ Andrew Howroyd, Aug 09 2018
Formula
From Andrew Howroyd, Aug 09 2018: (Start)
a(n) = 5*a(n-1) - 8*a(n-2) + 3*a(n-3) + 3*a(n-4) - 2*a(n-5).
G.f.: (1 - 3*x + 5*x^2 - 6*x^3 + 4*x^4)/((1 - x)^2*(1 - 2*x)*(1 - x - x^2)).
(End)
Extensions
Terms a(10) and beyond from Andrew Howroyd, Aug 09 2018