A025411 Numbers that are the sum of 4 distinct positive cubes.

100, 161, 198, 217, 224, 252, 289, 308, 315, 350, 369, 376, 379, 406, 413, 416, 432, 435, 442, 477, 496, 503, 533, 540, 548, 559, 568, 585, 587, 594, 604, 611, 624, 631, 646, 650, 665, 672, 685, 692, 702, 709, 711, 728, 737, 748, 756, 763, 765, 793, 800, 802, 819, 821, 828, 854, 861, 863, 864, 880, 882, 883, 889, 890, 917, 919, 920, 926, 927, 945, 946, 954, 973, 980, 981, 988, 1007, 1010, 1017, 1036

Offset

1,1

Comments

First differs from A025408 at a(80)=1036. - Ray Chandler, Feb 19 2005

Links

Table of n, a(n) for n=1..80.

Example

a(80) = 1036 = 1+8+27+1000 = 27+64+216+729.

Maple

isA025411:= proc(n)
    local a, x, y, z, wcu ;
    for x from 1 do
        if 4*x^3 > n then
            return false;
            end if;
        for y from x+1 do
            if x^3+3*y^3 > n then
                break;
            end if;
            for z from y+1 do
                if x^3+y^3+2*z^3 > n then
                    break;
                end if;
                wcu := n-x^3-y^3-z^3 ;
                if wcu > z^3 and isA000578(wcu) then
                    return true ;
                end if;
            end do
        end do:
    end do:
end proc:
for n from 1 to 1100 do
    if isA025411(n) then
        printf("%d, ", n) ;
    end if;
end do: # R. J. Mathar, Jun 15 2018

Mathematica

smax = 1036;
imax = smax^(1/3) // Ceiling;
Table[If[Less[i, j, k, l] && (s = i^3 + j^3 + k^3 + l^3) <= smax, s, Nothing], {i, 1, imax}, {j, i+1, imax}, {k, j+1, imax}, {l, k+1, imax}] // Flatten // Union (* Jean-François Alcover, Jun 26 2023 *)

Crossrefs

Cf. A025408, A025409, A025410, A025412, A025413.

Sequence in context: A004263 A004264 A308738 * A025408 A068805 A369417

Adjacent sequences: A025408 A025409 A025410 * A025412 A025413 A025414

Keyword

nonn

Author

David W. Wilson

Extensions

More terms from Ray Chandler, Feb 19 2005

Status

approved