|
| |
|
|
A072944
|
|
a(1)=2, a(n+1) = 2*a(n) - Phi(a(n)) where Phi is the Euler totient function.
|
|
0
| |
|
|
2, 3, 4, 6, 10, 16, 24, 40, 64, 96, 160, 256, 384, 640, 1024, 1536, 2560, 4096, 6144, 10240, 16384, 24576, 40960, 65536, 98304, 163840, 262144, 393216, 655360, 1048576, 1572864, 2621440, 4194304, 6291456, 10485760, 16777216, 25165824
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| For any x=f(1) positive integer>1 there is an integer N(x) such that for any n>=N(x) f(n)/f(n-3)=4. N(2)=6 N(3)=5 N(4)=5 ... N(1479) =20. Conjecture: N(x) is asymptotic to C*Log(x) with C=0.3..... ( 3/10 < C < 4/10).
|
|
|
FORMULA
| a(1)=2, a(2)=3, a(3)=4, a(4)=6, a(5)=10 and for n> 5 a(n) = 4*a(n-3)
|
|
|
CROSSREFS
| Sequence in context: A098855 A143283 A104767 * A024722 A024965 A018142
Adjacent sequences: A072941 A072942 A072943 * A072945 A072946 A072947
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 14 2002
|
| |
|
|
