login
A216659
Number of n-digit 9th powers.
2
2, 0, 1, 0, 1, 1, 1, 2, 2, 3, 4, 5, 6, 8, 11, 13, 18, 22, 30, 37, 49, 63, 81, 105, 135, 175, 225, 292, 377, 486, 628, 811, 1048, 1353, 1748, 2257, 2916, 3766, 4863, 6281, 8113, 10477, 13533, 17478, 22573, 29155, 37656, 48633, 62812, 81126, 104777, 135326
OFFSET
1,1
LINKS
EXAMPLE
a(1) = 2: 0, 1.
a(3) = 1: 512.
a(5) = 1: 19683.
a(9) = 2: 134217728, 387420489.
a(10) = 3: 1000000000, 2357947691, 5159780352.
a(11) = 4: 10604499373, 20661046784, 38443359375, 68719476736.
MAPLE
r:= proc(n, k) local b; b:= iroot(n, k); b+`if`(b^k<n, 1, 0) end:
a:= n-> r(10^n, 9) -r(10^(n-1), 9) +`if`(n=1, 1, 0):
seq(a(n), n=1..60);
CROSSREFS
Column k=9 of A216653.
Sequence in context: A015879 A230000 A016242 * A321396 A141747 A239706
KEYWORD
nonn,base
AUTHOR
Alois P. Heinz, Sep 12 2012
STATUS
approved