OFFSET
0,3
COMMENTS
LINKS
FORMULA
a(n+1) = a(n) + A107751(n).
For k >= 0, 0 <= i <= 3*2^k:
a(6*2^k + i) = a(3*2^k + i) + 4*2^k,
a(9*2^k + i) = a(3*2^k + i) + 8*2^k.
a(n) = n - sign(floor(n/3)) + floor( (1/2)*sum_{i=1..n} ( ceiling((i+2)/3) - floor((i+2)/3) ) ). - Wesley Ivan Hurt, Jun 16 2014
Conjectures from Colin Barker, Jul 24 2017: (Start)
G.f.: x*(1+x)*(1+x^2-x^3+x^4) / ((1-x)^2*(1+x+x^2)).
a(n) = a(n-1) + a(n-3) - a(n-4) for n>3.
(End)
MATHEMATICA
Table[n - Sign[Floor[n/3]] + Floor[(1/2) Sum[Ceiling[(i + 2)/3] - Floor[(i + 2)/3], {i, n}]], {n, 0, 50}] (* Wesley Ivan Hurt, Jun 16 2014 *)
PROG
(Haskell)
a107750 n = a107750_list !! n
a107750_list = 0 : f 0 where
f x = y : f y where
y = head [z | z <- [x + 1 ..], a023416 z /= a023416 x]
-- Reinhard Zumkeller, Jul 07 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 23 2005
STATUS
approved