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Search: id:A117308
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| A117308 |
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Numbers for which (phi(n))^2+phi(n)+1 is a palindrome. |
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+0
1
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| 1, 2, 3, 4, 6, 11, 19, 22, 27, 38, 54, 101, 125, 202, 250, 1111, 1189, 1207, 1243, 1255, 1375, 1405, 1595, 1779, 1875, 1877, 1957, 2008, 2149, 2175, 2222, 2235, 2248, 2272, 2372, 2378, 2384, 2414, 2486, 2500, 2510, 2552, 2750, 2757, 2763, 2781, 2810, 2840
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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19 is in the sequence because (phi(19))^2+phi(19)+1=18^2+18+1=343, which is a palindrome.
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MAPLE
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rev:=proc(n) local nn: nn:=convert(n, base, 10): add(nn[nops(nn)+1-j]*10^(j-1), j=1..nops(nn)) end: with(numtheory): a:=proc(m) if rev(phi(m)^2+phi(m)+1)=phi(m)^2+phi(m)+1 then m else fi end: seq(a(m), m=1..3500); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 30 2006
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CROSSREFS
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Sequence in context: A066615 A133951 A111124 this_sequence A114412 A016038 A003099
Adjacent sequences: A117305 A117306 A117307 this_sequence A117309 A117310 A117311
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KEYWORD
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base,nonn
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AUTHOR
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Luc Stevens (lms022(AT)yahoo.com), Apr 24 2006
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 30 2006
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