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A270393
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Another variant of narcissistic numbers: integers n equal the product of squared digits of n divided by the sum of digits of n, i.e., n = A007954(n)^2/A007953(n).
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0
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1, 2, 3, 4, 5, 6, 7, 8, 9, 36, 735
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OFFSET
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1,2
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COMMENTS
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No other terms below 10^300. - Max Alekseyev, May 31 2018
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LINKS
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Table of n, a(n) for n=1..11.
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EXAMPLE
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36 is a term because 36 = (3^2*6^2)/(3+6).
735 is a term because 735 = (7^2*3^2*5^2)/(7+3+5).
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MATHEMATICA
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Select[Range[10^6], Function[k, k == Apply[Times, #^2]/(Total@ #) &@ IntegerDigits@ k]@ # &] (* Michael De Vlieger, Mar 16 2016 *)
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PROG
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(PARI) { is_A270393(n) = my(d = digits(n)); n == vecprod(d)^2/vecsum(d); } \\ Michel Marcus, Mar 17 2016
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CROSSREFS
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Subsequence of A128606.
Cf. A005188, A257554.
Sequence in context: A316147 A080161 A257554 * A257787 A098771 A276810
Adjacent sequences: A270390 A270391 A270392 * A270394 A270395 A270396
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KEYWORD
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nonn,more,base
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AUTHOR
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José de Jesús Camacho Medina, Mar 16 2016
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STATUS
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approved
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