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 A109027 7-almost primes (A046308) whose digit reversal is different and also has 7 prime factors (with multiplicity). "Emirp Tsomla-7.". 6
 8820, 21240, 21708, 21780, 21920, 23280, 23472, 23625, 23800, 25560, 25584, 25758, 26280, 27432, 27504, 27888, 27900, 28836, 29250, 29403, 29736, 29970, 30492, 34884, 36828, 40338, 40572, 40950, 41976, 42228, 42984, 43659, 43956, 44128 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This sequence is the k = 7 instance of the series which begins with k = 1 (emirps), k = 2 (emirpimes), k = 3 (emirp tsomla-3 = A109023), k = 4 (emirp tsomla-4 = A109024), k = 5 (emirp tsomla-5 = A109025), k = 6 (emirp tsomla-6 = A109026). 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 Tsomla-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(20) = 29403 is in this sequence because 29403 = 3^5 * 11^2 is a 7-almost prime and reverse(29403) = 30492 = 2^2 * 3^2 * 7 * 11^2 is also a 7-almost prime. MATHEMATICA Select[Range, !PalindromeQ[#]&&PrimeOmega[#]==PrimeOmega[ IntegerReverse[ #]] ==7&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 02 2019 *) CROSSREFS Cf. A046308, A006567, A097393, A109018, A109023-A109026, A109028-A109131. Sequence in context: A270609 A230335 A183752 * A237761 A186582 A147529 Adjacent sequences: A109024 A109025 A109026 * A109028 A109029 A109030 KEYWORD nonn,base AUTHOR Jonathan Vos Post, Jun 16 2005 STATUS approved

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Last modified March 28 16:30 EDT 2023. Contains 361596 sequences. (Running on oeis4.)