|
Search: id:A110604
|
|
|
| A110604 |
|
Numbers n whose base 6 representations, interpreted as base 10 integers, are semiprimes. |
|
+0
7
|
|
| 4, 6, 10, 11, 13, 14, 17, 21, 22, 23, 31, 35, 43, 47, 49, 50, 51, 57, 58, 61, 62, 63, 65, 71, 73, 74, 75, 77, 81, 82, 83, 85, 95, 105, 106, 109, 110, 111, 113, 118, 121, 123, 130, 131, 133, 143, 147, 151, 153, 155, 158, 173, 175, 177, 178, 181, 182, 185, 187, 190, 191
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
A108873 is the equivalent using base 3. A110602 is the equivalent using base 4. A110603 is the equivalent using base 5. A110605 is the equivalent using base 7. A110606 is the equivalent using base 8. A110607 is the equivalent using base 9.
|
|
EXAMPLE
|
a(1) = 4 because 4 (base 6) = 4 and 4 (base 10) = 2 * 2, a semiprime (A001358).
a(2) = 6 because 6 (base 6) = 10 and 10 (base 10) = 2 * 5.
a(3) = 10 because 10 (base 6) = 14 and 14 (base 10) = 2 * 7.
a(4) = 11 because 11 (base 6) = 15 and 15 (base 10) = 3 * 5.
a(5) = 13 because 13 (base 6) = 21 and 21 (base 10) = 3 * 7.
|
|
MATHEMATICA
|
Select[Range[191], Plus @@ Last /@ FactorInteger[FromDigits[IntegerDigits[ #, 6]]] == 2 &] (*Chandler*)
|
|
CROSSREFS
|
Cf. A001358, A007092, A108873, A110602, A110603, A110605, A110606, A110607.
Sequence in context: A117003 A057670 A141780 this_sequence A109270 A137877 A163164
Adjacent sequences: A110601 A110602 A110603 this_sequence A110605 A110606 A110607
|
|
KEYWORD
|
base,easy,nonn
|
|
AUTHOR
|
Jonathan Vos Post (jvospost3(AT)gmail.com), Jul 30 2005
|
|
EXTENSIONS
|
Corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Aug 05 2005
|
|
|
Search completed in 0.002 seconds
|
