A022551 Numbers that are the sum of 2 squares and a nonnegative cube.

0, 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Jean-François Alcover, Table of n, a(n) for n = 1..943
• Index entries for sequences related to sums of squares

Crossrefs

Complement of A022552.

Programs

Maple

isA022551 := proc(n)
    local a,b,c ;
    for c from 0 do
        if c^3 > n then
            return false;
        end if;
        for a from 0 do
            b2 := n-c^3-a^2 ;
            if b2 < a^2 then
                break;
            end if;
            if issqr(b2) then
                return true;
            end if;
        end do:
    end do:
end proc: # R. J. Mathar, Sep 02 2016

Mathematica

max = 1000;
Table[x^2 + y^2 + z^3, {x, 0, Sqrt[max]}, {y, x, Sqrt[max - x^2]}, {z, 0, (max - x^2 - y^2)^(1/3)}] // Flatten // Union // Select[#, # <= max&]& (* Jean-François Alcover, Mar 23 2020 *)