|
| |
|
|
A110604
|
|
Numbers n whose base 6 representations, interpreted as base 10 integers, are semiprimes.
|
|
6
| |
|
|
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; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| 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*)
Select[Range[200], PrimeOmega[FromDigits[IntegerDigits[#, 6]]]==2&] (* From Harvey P. Dale, Oct 02 2011 *)
|
|
|
CROSSREFS
| Cf. A001358, A007092, A108873, A110602, A110603, A110605, A110606, A110607.
Sequence in context: A171615 A141780 A185002 * A109270 A187331 A184923
Adjacent sequences: A110601 A110602 A110603 * 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
|
| |
|
|
