A062941 Number of n-digit cubes (0 is included as a single-digit number).

3, 2, 5, 12, 25, 53, 116, 249, 535, 1155, 2487, 5358, 11545, 24871, 53584, 115444, 248715, 535841, 1154435, 2487154, 5358411, 11544347, 24871542, 53584111, 115443470, 248715414, 535841116, 1154434691, 2487154143, 5358411166

Offset

1,1

Comments

Sum of first 3n terms = 10^n.

Links

Harry J. Smith, Table of n, a(n) for n = 1..300

Example

a(3) = 5 as there are 5 three-digit cubes: 125, 216, 343, 512 and 729.

Maple

r:= proc(n, k) local b; b:= iroot(n, k); b+`if`(b^k<n, 1, 0) end:
a:= n-> r(10^n, 3) -r(10^(n-1), 3) +`if`(n=1, 1, 0):
seq(a(n), n=1..40);  # Alois P. Heinz, Sep 12 2012

Prog

(PARI) { default(realprecision, 300); p=1; b=-1; for (n=1, 300, p*=10; c=b; b=floor((p - 1)^(1/3)); write("b062941.txt", n, " ", b - c) ) } \\ Harry J. Smith, Aug 14 2009

Crossrefs

Cf. A062940.

Column k=3 of A216653.

Sequence in context: A075146 A353403 A300939 * A211018 A374428 A290427

Adjacent sequences: A062938 A062939 A062940 * A062942 A062943 A062944

Keyword

base,nonn

Author

Amarnath Murthy, Jul 07 2001

Extensions

Corrected and extended by Dean Hickerson, Jul 10 2001

Offset changed from 0 to 1 by Harry J. Smith, Aug 14 2009

Status

approved