A330708 Numbers that are not the sum of 2 nonzero squares and a positive cube.

0, 1, 2, 4, 5, 7, 8, 12, 15, 17, 20, 22, 23, 24, 31, 36, 39, 43, 50, 55, 57, 63, 65, 70, 71, 78, 87, 94, 103, 111, 113, 115, 119, 120, 134, 139, 141, 148, 160, 167, 169, 185, 204, 211, 254, 263, 267, 279, 283, 286, 302, 311, 312, 331, 335, 342, 349, 379, 391

Offset

1,3

Comments

A022552 is a subsequence.

a(490) = A022552(434) = 5042631. No more terms <= 4 * 10^7.

Links

Robert Israel, Table of n, a(n) for n = 1..490

Maple

N:= 500: # for terms <= N
G1:= add(x^(i^2), i=1..floor(sqrt(N))):
G2:= add(x^(i^3), i=1..floor(N^(1/3))):
G:= expand(G1^2*G2):
select(t -> coeff(G, x, t)=0, [$0..N]); # Robert Israel, Jun 12 2020

Mathematica

m = 0;
n = 400.;
t = Union@Flatten@Table[x^2 + y^2 + z^3, {x, (n/2)^(1/2)}, {y, x, (n - x^2)^(1/2)}, {z, If[x^2 + y^2 < m, Floor[(m - 1 - x^2 - y^2)^(1/3)] + 1, 1], (n - x^2 - y^2)^(1/3)}];
Complement[Range[m, n], t]

Crossrefs

Cf. A022552, A000534, A004214.

Sequence in context: A350417 A176193 A072920 * A107899 A032924 A005125

Adjacent sequences: A330705 A330706 A330707 * A330709 A330710 A330711

Keyword

nonn

Author

XU Pingya, Jun 08 2020

Status

approved