

A216390


Number of values of k for which sigma(k) is a permutation of decimal digits of k, for 10^(n1) < k < 10^n.


0




OFFSET

1,3


LINKS

Table of n, a(n) for n=1..9.


FORMULA

a(n) = # { k in A115920  10^(n1) < 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^(n1), 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



