|
Search: id:A132857
|
|
|
| A132857 |
|
a(0)=1. a(n) = phi(n+a(n-1)), for n>=1, where phi(m) is the number of positive integers which are <= m and are coprime to m. |
|
+0
1
|
|
| 1, 1, 2, 4, 4, 6, 4, 10, 6, 8, 6, 16, 12, 20, 16, 30, 22, 24, 12, 30, 20, 40, 30, 52, 36, 60, 42, 44, 24, 52, 40, 70, 32, 48, 40, 40, 36, 72, 40, 78, 58, 60, 32, 40, 24, 44, 24, 70, 58, 106, 48, 60, 48, 100, 60, 88, 48, 48, 52, 72, 40, 100, 54, 72, 64, 84, 40, 106, 56, 100
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
LINKS
|
Leroy Quet, Home Page (listed in lieu of email address)
|
|
EXAMPLE
|
a(8) + 9 = 6 + 9 = 15. There are 8 positive integers that are <= 15 and are relatively prime to 15. So a(9) = 8.
|
|
MATHEMATICA
|
a = {1}; For[n = 1, n < 90, n++, AppendTo[a, EulerPhi[n + a[[ -1]]]]]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Nov 24 2007
|
|
CROSSREFS
|
Sequence in context: A091666 A084290 A062011 this_sequence A152782 A057696 A057697
Adjacent sequences: A132854 A132855 A132856 this_sequence A132858 A132859 A132860
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Leroy Quet Nov 21 2007
|
|
EXTENSIONS
|
More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Nov 24 2007
|
|
|
Search completed in 0.002 seconds
|
