

A109026


6almost primes (A046306) whose digit reversal is different and also has 6 prime factors (with multiplicity). "Emirp Tsolma6.".


8



2576, 2970, 4284, 4356, 4410, 4600, 4698, 4824, 5265, 5625, 6534, 6752, 6900, 8250, 8964, 10710, 10890, 13140, 13986, 16236, 16335, 17577, 18504, 19494, 20286, 20574, 21114, 21150, 21160, 21336, 21492, 21576, 21609, 21900, 21996, 22392, 22770
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OFFSET

1,1


COMMENTS

This sequence is the k = 6 instance of the series which begins with k = 1 (emirps), k = 2 (emirpimes), k = 3 (emirp tsolma3 = A109023), k = 4 (emirp tsolma4 = A109024), k = 5 (emirp tsolma5 = A109025).
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 Tsolma3 and Related Integer Sequences." Forthcoming paper on this sequence.


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..3500
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) = 2576 is in this sequence because 2576 = 2^4 * 7 * 23 is a 6almost prime and reverse(2576) = 6752 = 2^5 * 211 is also a 6almost prime.


MATHEMATICA

Select[Range[23000], !PalindromeQ[#]&&Total[FactorInteger[#][[All, 2]]] == Total[FactorInteger[IntegerReverse[#]][[All, 2]]]==6&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 10 2017 *)


CROSSREFS

Cf. A046306, A006567, A097393, A109018, A109023A109025, A109027A109131.
Sequence in context: A260104 A031789 A001294 * A217183 A034415 A201510
Adjacent sequences: A109023 A109024 A109025 * A109027 A109028 A109029


KEYWORD

nonn,base


AUTHOR

Jonathan Vos Post, Jun 16 2005


STATUS

approved



