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Search: id:A109028
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| A109028 |
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8-almost primes (A046310) whose digit reversal is different and also has 8 prime factors (with multiplicity). "Emirp Tsolma-8.". |
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+0
6
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| 16560, 25515, 27864, 42480, 46872, 51552, 57348, 61488, 65448, 67797, 69408, 69840, 79776, 80496, 84375, 84456, 88416, 105336, 119448, 125928, 160416, 167076, 202032, 204984, 206928, 210960, 211104, 211464, 213750, 213792, 213920, 213984
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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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).
The Mathematica code for this was written by Ray Chandler who extended this sequence. He also has more values.
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REFERENCES
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Jonathan Vos Post, "1066 and All That: Emirp Tsolma-3 and Related Integer Sequences." Forthcoming paper on this sequence.
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LINKS
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Eric Weisstein's World of Mathematics, Almost Prime.
Eric Weisstein's World of Mathematics, Emirp.
Eric Weisstein and Jonathan Vos Post, Emirpimes.
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EXAMPLE
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a(2) = 25515 is in this sequence because 25515 = 3^6 * 5 * 7 is an 8-almost prime and reverse(25515) = 51552 = 2^5 * 3^2 * 179 is also an 8-almost prime.
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CROSSREFS
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Cf. A046310, A006567, A097393, A109018, A109023-A109027, A109029-A109131.
Sequence in context: A057680 A157796 A091089 this_sequence A057329 A108843 A128383
Adjacent sequences: A109025 A109026 A109027 this_sequence A109029 A109030 A109031
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KEYWORD
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nonn,base
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Jun 16 2005
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