|
Search: id:A109029
|
|
|
| A109029 |
|
9-almost primes (A046312) whose digit reversal is different and also has 9 prime factors (with multiplicity). "Emirp Tsolma-9.". |
|
+0
5
|
|
| 21168, 23424, 23616, 27456, 41184, 42432, 48114, 61632, 65472, 86112, 211410, 212256, 213192, 215232, 217440, 219072, 230208, 232512, 236925, 236928, 238656, 238680, 251100, 251505, 251748, 253824, 255024, 255960, 257856, 259968, 270912
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
This sequence is the k = 8 instance of the series which begins with k = 1 (emirps), k = 2 (emirpimes), k = 3 (emirp tsolma-3 = A109023), k = 4 (emirp tsolma-4 = A109024), k = 5 (emirp tsolma-5 = A109025), k = 6 (emirp tsolma-6 = A109026), k = 7 (emirp tsolma-7 = A109027), k = 8 (emirp tsolma-8 = A109028).
The Mathematica code for this was written by Ray Chandler who extended this sequence. He also has more values.
|
|
REFERENCES
|
Jonathan Vos Post, "1066 and All That: Emirp Tsolma-3 and Related Integer Sequences." Forthcoming paper on this sequence.
|
|
LINKS
|
Eric Weisstein's World of Mathematics, Almost Prime.
Eric Weisstein's World of Mathematics, Emirp.
Eric Weisstein and Jonathan Vos Post, Emirpimes.
|
|
EXAMPLE
|
a(1) = 21168 is in this sequence because 21168 = 2^4 * 3^3 * 7^2 is a 9-almost prime and reverse(21168) = 86112 = 2^5 * 3^2 * 13 * 23 is also a 9-almost prime.
|
|
CROSSREFS
|
Cf. A046312, A006567, A097393, A109018, A109023-A109028, A109030-A109131.
Sequence in context: A043654 A157083 A097239 this_sequence A083361 A086477 A096554
Adjacent sequences: A109026 A109027 A109028 this_sequence A109030 A109031 A109032
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
Jonathan Vos Post (jvospost3(AT)gmail.com), Jun 16 2005
|
|
|
Search completed in 0.002 seconds
|
