A216658 Number of n-digit 8th powers.

2, 0, 1, 1, 1, 1, 2, 2, 4, 4, 6, 8, 11, 14, 18, 25, 34, 44, 60, 79, 105, 141, 187, 250, 334, 445, 593, 791, 1054, 1407, 1875, 2501, 3336, 4447, 5931, 7909, 10547, 14065, 18755, 25010, 33353, 44475, 59310, 79090, 105469, 140645, 187553, 250105, 333522, 444758

Offset

1,1

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Example

a(1) = 2: 0, 1.
a(3) = 1: 256.
a(4) = 1: 6561.
a(9) = 4: 100000000, 214358881, 429981696, 815730721.
a(10) = 4: 1475789056, 2562890625, 4294967296, 6975757441.
a(11) = 6: 11019960576, 16983563041, 25600000000, 37822859361, 54875873536, 78310985281.

Maple

r:= proc(n, k) local b; b:= iroot(n, k); b+`if`(b^k<n, 1, 0) end:
a:= n-> r(10^n, 8) -r(10^(n-1), 8) +`if`(n=1, 1, 0):
seq(a(n), n=1..60);

Mathematica

Join[{2, 0}, Tally[IntegerLength[Range[2, 18*10^5]^8]][[;; , 2]]] (* Harvey P. Dale, Sep 15 2024 *)

Crossrefs

Column k=8 of A216653.

Sequence in context: A369258 A337930 A340691 * A214020 A029425 A219055

Adjacent sequences: A216655 A216656 A216657 * A216659 A216660 A216661

Keyword

nonn,base

Author

Alois P. Heinz, Sep 12 2012

Status

approved