OFFSET
0,2
COMMENTS
Previous name was: One half of second column (m=1) of triangle A142963.
Essentially a duplicate of A050488. - Johannes W. Meijer, Feb 20 2009
REFERENCES
Eric Billault, Walter Damin, Robert Ferréol, Rodolphe Garin, MPSI Classes Prépas - Khôlles de Maths, Exercices corrigés, Ellipses, 2012, exercice 2.22 (1) pp 26, 43-44.
LINKS
FORMULA
a(n) = A142693(n+2,1)/2.
From Johannes W. Meijer, Feb 20 2009: (Start)
a(n) = 4a(n-1) - 5a(n-2) + 2a(n-3) for n > 2 with a(0) = 1, a(1) = 5, a(2) = 15.
G.f.: (1+z)/((1-z)^2*(1-2*z)). (End)
a(n) = Sum_{i=0..n} Sum_{j=0..n} 2^min(i,j) (Billault et al) (compare with A339771 that has max instead of min). - Bernard Schott, Dec 16 2020
E.g.f.: 6*exp(2*x) - exp(x)*(5 + 2*x). - Stefano Spezia, Dec 17 2020
EXAMPLE
a(3) = 6*2^3 - 2*3 - 5 = 37.
MAPLE
seq(6*2^n-2*n-5, n=0..40); # Bernard Schott, Dec 16 2020
PROG
(PARI) Vec((1+z)/((1-z)^2*(1-2*z)) + O(z^50)) \\ Michel Marcus, Jun 18 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Sep 15 2008
EXTENSIONS
New name using a formula of Bernard Schott by Peter Luschny, Dec 17 2020
STATUS
approved