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A067599
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Decimal encoding of the prime factorization of n.
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11
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21, 31, 22, 51, 2131, 71, 23, 32, 2151, 111, 2231, 131, 2171, 3151, 24, 171, 2132, 191, 2251, 3171, 21111, 231, 2331, 52, 21131, 33, 2271, 291, 213151, 311, 25, 31111, 21171, 5171, 2232, 371, 21191, 31131, 2351, 411, 213171, 431, 22111, 3251, 21231
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,1
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COMMENTS
| If n has prime factorization p_1^e_1 * ... * p_r^e_r with p_1 < ... < p_r, then its decimal encoding is p_1 e_1...p_r e_r. For example, 15 = 3^1 * 5^1, so has decimal encoding 3151.
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EXAMPLE
| The prime factorization of 24 = 2^3 * 3^1 with corresponding encoding 2331. So a(24) = 2331.
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MATHEMATICA
| f[n_] := FromDigits[ Flatten[ IntegerDigits[ FactorInteger[ n]]]]; Table[ f[n], {n, 2, 50} ]
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CROSSREFS
| Cf. A037276, A080670, A112375. See A068633 for another version.
Sequence in context: A116116 A079394 A112375 * A123846 A168000 A031889
Adjacent sequences: A067596 A067597 A067598 * A067600 A067601 A067602
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KEYWORD
| base,easy,nonn
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AUTHOR
| Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Jan 31 2002
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EXTENSIONS
| Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 02 2002
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