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A263481 Total number of n-digit positive integers with multiplicative digital root value 8. 7
1, 22, 138, 889, 4921, 26687, 154539, 870270, 4437621, 20367762, 86589471, 388661761, 2366418106, 18602433227, 142978182070, 952075901928, 5434361620523, 27064481351856, 120477919973804, 497320625548529, 2051776298637086, 9590295679377844, 54933121828772931 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
First differences of A263475.
LINKS
Hiroaki Yamanouchi, Table of n, a(n) for n = 1..50
FORMULA
A263476(n) + A000012(n) + A263477(n) + A000027(n) + A263478(n) + A263479(n) + A263480(n) + A000027(n) + a(n) + A000217(n) = A052268(n).
MATHEMATICA
Last /@ Tally@ IntegerLength@ Select[Range@ 1000000, FixedPoint[Times @@ IntegerDigits@ # &, #] == 8 &] (* Michael De Vlieger, Oct 21 2015 *)
PROG
(PARI) t(k) = {while(k>9, k=prod(i=1, #k=digits(k), k[i])); k}
a(n) = sum(i=10^(n-1), 10^n - 1, if(t(i) == 8, 1, 0)); \\ Altug Alkan, Oct 19 2015
CROSSREFS
Sequence in context: A041936 A254699 A183909 * A238170 A275799 A185397
KEYWORD
nonn,base
AUTHOR
Martin Renner, Oct 19 2015
EXTENSIONS
a(9)-a(23) from Hiroaki Yamanouchi, Oct 25 2015
STATUS
approved

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Last modified April 15 10:24 EDT 2024. Contains 371681 sequences. (Running on oeis4.)