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A022552 Numbers that are not the sum of 2 squares and a nonnegative cube. 21
7, 15, 22, 23, 39, 55, 70, 71, 78, 87, 94, 103, 111, 115, 119, 120, 139, 167, 211, 254, 263, 267, 279, 286, 302, 311, 312, 331, 335, 342, 391, 403, 435, 454, 455, 470, 475, 499, 518, 559, 590, 595, 598, 622, 643, 659, 691, 695, 715, 727, 771 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
There are 434 terms < 6 * 10^7 of which the largest is 5042631 ~= 5 * 10^6. Is this sequence finite? - David A. Corneth, Jun 23 2018
No more terms < 10^10. - Mauro Fiorentini, Jan 26 2019
For n = 1..434, a(n) + 2 is a term of A022551. Zhi-Wei Sun conjectures that Any n can be written as x^2 + y^2 + z^3 + 0(or 2). - XU Pingya, Jun 02 2020
LINKS
R. J. Mathar, David A. Corneth, Table of n, a(n) for n = 1..434 (First 325 terms from R. J. Mathar, now terms < 6 * 10^7)
Steven Finch, Pattern-Avoiding Permutations [Broken link?]
Steven Finch, Pattern-Avoiding Permutations [Cached copy, with permission]
W. Jagy and I. Kaplansky, Sums of Squares, Cubes and Higher Powers, Experimental Mathematics, vol. 4 (1995) pp. 169-173.
Zhi-Wei Sun, New Conjectures on Representations of Integers (I), Nanjing Univ. J. Math. Biquarterly 34(2017), No.2, p. 110.
MAPLE
isA022552 := proc(n)
not isA022551(n) ;
end proc:
n := 1:
for c from 0 do
if isA022552(c) then
printf("%d %d\n", n, c);
n := n+1 ;
end if;
end do: # R. J. Mathar, Sep 02 2016
MATHEMATICA
max = 10^6;
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&]& // Complement[Range[max], #]& (* Jean-François Alcover, Mar 23 2020 *)
CROSSREFS
Complement of A022551.
Sequence in context: A053354 A346197 A274700 * A082658 A022389 A041225
KEYWORD
nonn
AUTHOR
STATUS
approved

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Last modified March 18 22:50 EDT 2024. Contains 370951 sequences. (Running on oeis4.)