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 A216390 Number of values of k for which sigma(k) is a permutation of decimal digits of k, for 10^(n-1) < k < 10^n. 0
 1, 1, 5, 10, 47, 200, 842, 4698, 28831 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS FORMULA a(n) = # { k in A115920 | 10^(n-1) < k < 10^n }. - M. F. Hasler, Feb 24 2014 EXAMPLE a(3) = 5 because the values of k satisfying the condition for 10^2 < k < 10^3 are {258, 270, 276, 609, 639}. - V. Raman, Feb 18 2014 PROG (PARI) a(n)=sum(k=10^(n-1), 10^n, vecsort(digits(k)) == vecsort(digits(sigma(k)))) \\ V. Raman, Feb 18 2014, based on edits by M. F. Hasler CROSSREFS Cf. A115920, A000203. Sequence in context: A035406 A103932 A034190 * A305476 A270089 A336582 Adjacent sequences:  A216387 A216388 A216389 * A216391 A216392 A216393 KEYWORD nonn,base,more AUTHOR V. Raman, Sep 06 2012 EXTENSIONS a(9) from Jinyuan Wang, Mar 02 2020 STATUS approved

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Last modified September 30 03:03 EDT 2020. Contains 337432 sequences. (Running on oeis4.)