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Search: id:A075813
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| A075813 |
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Palindromic even numbers with exactly 2 prime factors (counted with multiplicity). Equivalently, palindromic numbers of the form 2*p with p prime. |
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+0
1
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| 4, 6, 22, 202, 262, 454, 626, 818, 838, 878, 898, 20302, 20602, 22322, 22522, 22622, 22822, 24142, 24842, 26662, 26762, 28682, 41014, 41414, 41614, 41714, 43034, 43234, 43534, 43634, 45454, 45554, 45754, 47074, 47374, 47774, 49094, 49394
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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4=2^2, 6=2*3 and 22=2*11 are palindromic, even and have exactly 2 prime factors.
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MAPLE
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test := proc(n) local d; d := convert(n, base, 10); return ListTools[Reverse](d)=d and numtheory[bigomega](n)=2; end; a := []; for n from 2 to 50000 by 2 do if test(n) then a := [op(a), n]; end; od; a;
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CROSSREFS
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Cf. A001747.
Sequence in context: A151519 A061595 A062940 this_sequence A004032 A107952 A123046
Adjacent sequences: A075810 A075811 A075812 this_sequence A075814 A075815 A075816
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KEYWORD
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nonn,base
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AUTHOR
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Jani Melik (jani_melik(AT)hotmail.com), Oct 13 2002
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EXTENSIONS
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Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Oct 21 2002
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