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A329026
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Numbers k such that k = Product (p_j^e_j) = concatenation (pi(p_j)), where pi = A000720.
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1
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OFFSET
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1,1
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COMMENTS
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Numbers k such that k equals concatenation of indices of distinct prime factors of k, in increasing order.
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LINKS
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EXAMPLE
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2127 is a term because 2127 = 3 * 709 = prime(2) * prime(127) = concat(2, 127).
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MATHEMATICA
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a[n_] := FromDigits[Flatten@IntegerDigits@(PrimePi[#[[1]]] & /@ FactorInteger[n])]; Select[Range[2200], a[#] == # &]
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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