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Number of values of k for which sigma(k)-k is a permutation of decimal digits of k, for 10^(n-1) < k < 10^n.
0

%I #25 Jan 23 2016 13:09:17

%S 1,1,3,10,40,215,1224,6587,3387628,50507498

%N Number of values of k for which sigma(k)-k is a permutation of decimal digits of k, for 10^(n-1) < k < 10^n.

%F a(n) = # { k in A085844 | 10^(n-1) < k < 10^n }. - _M. F. Hasler_, Feb 24 2014

%e a(3) = 3 because the values of k satisfying the condition for 10^2 < k < 10^3 are {411, 496, 604}. - _V. Raman_, Feb 17 2014

%o (PARI) a(n)=sum(k=10^(n-1), 10^n, vecsort(digits(k)) == vecsort(digits(sigma(k)-k))) \\ _V. Raman_, Feb 17 2014, based on edits by _M. F. Hasler_

%Y Cf. A085844, A001065.

%K nonn,base,more

%O 1,3

%A _V. Raman_, Sep 06 2012

%E a(9)-a(10) from _Lars Blomberg_, Jan 23 2016