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A049328
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Numbers whose prime factors (taken with multiplicity) sum to 20.
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0
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51, 91, 130, 154, 156, 220, 264, 297, 392, 441, 525, 560, 625, 630, 672, 750, 756, 800, 900, 960, 1024, 1080, 1152, 1215, 1296, 1458
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OFFSET
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1,1
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COMMENTS
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Numbers whose prime factorization k = 2^i_1 * 3^i_2 * 5^i_3 * .. * 17^i_7 * 19^i_8 satisfies 2*i_1 + 3*i_2 + ... + 17*i_7 + 19*i_8 = 20. - N. J. A. Sloane, Jan 16 2019
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LINKS
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EXAMPLE
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E.g. 51 = 3 * 17 and 3 + 17 = 20. 1024 = 2^10 and 10*2 = 20.
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MATHEMATICA
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pfs20Q[n_]:=Total[#[[1]]#[[2]]&/@FactorInteger[n]]==20; Select[Range[ 10000], pfs20Q] (* Harvey P. Dale, Jan 17 2019 *)
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CROSSREFS
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Numbers k such that A001414(k) = 20.
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KEYWORD
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fini,full,nonn
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AUTHOR
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Rawlyn Watson (rawlyn(AT)chplayers.freeserve.co.uk)
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EXTENSIONS
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STATUS
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approved
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