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A260588
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Number of prime factors, counted with multiplicity, of A173426(n) = concatenation of (1, 2, ..., n, n-1, ..., 1).
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2
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0, 2, 4, 4, 4, 10, 4, 8, 8, 1, 2, 5, 3, 6, 7, 4, 5, 8, 6, 2, 6, 3, 4, 9, 2, 6, 11, 2, 4, 10, 4, 9, 8, 6, 6, 12, 3, 6, 8, 4, 6, 7, 3, 6
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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a(2) = 2 since A173426(2) = 121 = 11*11 has twice the factor 11.
a(21) = 6 since A173426(21) = 3 * 3 * 7 * 828703 * 94364768151913037621 * 250591098443370396365457961250972909.
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PROG
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CROSSREFS
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See A260587 for the variant where only distinct prime factors are counted.
See also A075023 and A075024 for the smallest and largest prime factor of the terms.
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KEYWORD
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nonn,base,hard,more
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AUTHOR
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EXTENSIONS
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a(38)-a(44) added using factordb.com by Jinyuan Wang, Mar 05 2020
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STATUS
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approved
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