OFFSET
1,2
LINKS
T. D. Noe, Table of n, a(n) for n=1..1000
J. M. Dover, On two OEIS conjectures, arXiv:1606.08033 [math.CO], 2016.
FORMULA
a(n) = 3 * A033485(n-1) - 1 = (3/2) * A000123(n-1) - 1, n>1. Proved by Jeremy Dover. - Ralf Stephan, Dec 08 2004
MATHEMATICA
a123[n_] := a123[n] = If[n == 0, 1, a123[Floor[n/2]] + a123[n-1]];
a[n_] := If[n == 1, 0, (3/2) a123[n-1] - 1]; Array[a, 50] (* Jean-François Alcover, Dec 04 2018 *)
PROG
(Python)
from itertools import islice
from collections import deque
def A022907_gen(): # generator of terms
aqueue, f, b, a = deque([2]), True, 1, 2
yield from (0, 2, 5)
while True:
a += b
yield 3*a-1
aqueue.append(a)
if f: b = aqueue.popleft()
f = not f
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved