A057903 - OEIS

%I #12 Feb 16 2025 08:32:43

%S 1,3,4,5,6,7,8,10,11,12,13,14,15,17,18,19,20,21,22,23,24,25,26,27,29,

%T 30,31,32,33,34,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,

%U 55,56,57,58,59,60,61,62,63,64,66,67,68,69,70,71,73,74,75,76,77,78,79

%N Positive integers that are not the sum of exactly two positive cubes.

%C Includes the cubes themselves (since a^3 = b^3 + c^3 has no solution, by the exponent 3 case of Fermat's Last Theorem), so is different from A022555.

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CubicNumber.html">Cubic number.</a>

%F Equals A022555 union A000578 - {0}.

%t pr[n_] := Select[ PowersRepresentations[n, 2, 3], FreeQ[#, 0]& ]; Select[ Range[80], pr[#] == {} &] (* _Jean-François Alcover_, Nov 08 2012 *)

%Y Cf. A022555, A000578.

%K nonn

%O 1,2

%A _Eric W. Weisstein_

%E Edited by _N. J. A. Sloane_, Sep 28 2007