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A085869
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Numbers n such that n and its digit reversal have the same prime signature.
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5
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1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 22, 26, 31, 33, 37, 39, 44, 51, 55, 58, 62, 66, 71, 73, 77, 79, 85, 88, 93, 97, 99, 101, 107, 111, 113, 115, 117, 121, 122, 123, 129, 131, 141, 143, 149, 151, 155, 157, 158, 159, 161, 165, 167, 169, 171, 177, 178, 179, 181
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OFFSET
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1,2
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LINKS
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EXAMPLE
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15 is a member 15 = 3*5 and 51 = 3*17 both have the prime signature p*q, p and q are primes.
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MAPLE
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s:= n-> sort(map(i-> i[2], ifactors(n)[2])):
a:= proc(n) option remember; local k; for k from 1+a(n-1) while
s(k)<>s((p-> parse(cat(seq(p[-i], i=1..length(p)))))(""||k)) do od; k
end: a(0):=0:
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jul 06 2003
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EXTENSIONS
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STATUS
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approved
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