|
|
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
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,4
|
|
LINKS
|
|
|
FORMULA
|
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
|
|
|
KEYWORD
|
nonn,easy,less
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|