|
Search: id:A086409
|
|
|
| A086409 |
|
a[1]=1; a[n+1]=a[n]-1 if prime[a[n]]+1)/2 is even, else a[n+1]=a[n]+4. |
|
+0
3
|
|
| 1, 5, 4, 3, 7, 11, 10, 14, 13, 17, 16, 20, 19, 18, 22, 21, 25, 29, 33, 37, 41, 40, 44, 48, 47, 46, 45, 49, 48, 47, 46, 45, 49, 48, 47, 46, 45, 49, 48, 47, 46, 45, 49, 48, 47, 46, 45, 49, 48, 47, 46
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
There is a cycle starting with a(26)=46: ...46,45,49,48,47,46,...
|
|
EXAMPLE
|
a(3)=4 because a(2)=5, prime[5]=11 (11+1)/2 is even and a(3)=a(2)-1
|
|
MATHEMATICA
|
b=1; Prepend[Table[b+=If[EvenQ[(Prime[b]+1)/2], -1, 4], {i, 52}], 1] (*A086409*)
|
|
CROSSREFS
|
Cf. A086407, A086408.
Sequence in context: A164360 A019762 A092156 this_sequence A154198 A086793 A070515
Adjacent sequences: A086406 A086407 A086408 this_sequence A086410 A086411 A086412
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Zak Seidov (zakseidov(AT)yahoo.com), Jul 18 2003
|
|
|
Search completed in 0.002 seconds
|
