A181404 Total number of positive integers below 10^n requiring 8 positive cubes in their representation as sum of cubes.

0, 3, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15

Offset

1,2

Comments

Also continued fraction expansion of (9+sqrt(229))/74. - Bruno Berselli, Sep 09 2011

Links

Table of n, a(n) for n=1..61.

Eric Weisstein's World of Mathematics, Waring's Problem

Index entries for linear recurrences with constant coefficients, signature (1).

Formula

A061439(n) + A181375(n) + A181377(n) + A181379(n) + A181381(n) + A181400(n) + A181402(n) + a(n) + A130130(n) = A002283(n).

a(n) = 15 for n > 2. - Charles R Greathouse IV, Sep 09 2011

G.f.: 3*x^2*(1+4*x)/(1-x). - Bruno Berselli, Sep 09 2011

E.g.f.: 3*(5*(exp(x) - 1 - x) - 2*x^2). - Stefano Spezia, May 21 2024

Mathematica

PadRight[{0, 3}, 100, 15] (* Paolo Xausa, May 24 2024 *)

Prog

(PARI) a(n)=if(n>2, 15, 3*n-3) \\ Charles R Greathouse IV, Oct 07 2015

Crossrefs

Cf. A018889, A010854.

Cf. A002283, A061439, A130130, A181375, A181377, A181379, A181381, A181400, A181402.

Sequence in context: A296842 A279925 A279534 * A096672 A344565 A289374

Adjacent sequences: A181401 A181402 A181403 * A181405 A181406 A181407

Keyword

nonn,easy

Author

Martin Renner, Jan 28 2011

Extensions

a(5)-a(7) from Lars Blomberg, May 04 2011

Status

approved