login
A131508
2*A000027 (natural numbers) sandwiched by tripled A001477 (nonnegative numbers).
1
0, 0, 0, 2, 1, 1, 1, 4, 2, 2, 2, 6, 3, 3, 3, 8, 4, 4, 4, 10, 5, 5, 5, 12, 6, 6, 6, 14, 7, 7, 7, 16, 8, 8, 8, 18, 9, 9, 9, 20, 10, 10, 10, 22, 11, 11, 11, 24, 12, 12, 12, 26, 13, 13, 13, 28, 14, 14, 14, 30, 15, 15, 15, 32, 16, 16, 16, 34, 17, 17, 17, 36, 18, 18, 18, 38, 19, 19, 19, 40, 20
OFFSET
0,4
LINKS
FORMULA
From Chai Wah Wu, Oct 24 2018: (Start)
a(n) = 2*a(n-4) - a(n-8) for n > 7.
G.f.: x^3*(x^3 + x^2 + x + 2)/(x^8 - 2*x^4 + 1). (End)
MAPLE
seq(coeff(series(x^3*(x^3+x^2+x+2)/(x^8-2*x^4+1), x, n+1), x, n), n = 0 .. 85); # Muniru A Asiru, Oct 24 2018
PROG
(GAP) a:=[0, 0, 0, 2, 1, 1, 1, 4];; for n in [9..85] do a[n]:=2*a[n-4]-a[n-8]; od; a; # Muniru A Asiru, Oct 24 2018
CROSSREFS
Sequence in context: A181876 A131505 A100092 * A305502 A308211 A140130
KEYWORD
nonn,easy,less
AUTHOR
Paul Curtz, Aug 13 2007
STATUS
approved