A379849 - OEIS

%I #20 Jan 19 2025 17:26:58

%S 1729,20683,40033,46683,134379,149389,195841,216027,216125,327763,

%T 402597,439101,443889,515375,558441,593047,684019,704977,842751,

%U 920673,984067,1073375,1080891,1195112,1260441,1533357,1566728,1845649,2048391,2301299,2418271,2585375,2622104,2691451,3242197

%N Taxicab numbers that are deficient.

%C 1566728 is the smaller even term in this sequence.

%e 1729 = 7*13*19 is a term because it is a Taxicab number (1^3+12^3 = 9^3+10^3) and it is larger than the sum of its proper divisors (1+7+13+19+91+133+247 = 511).

%e 13832 = 2^3*7*13*19 it is not a term because it is a Taxicab number (13832 = 2^3+24^3 = 18^3+20^3) but it is smaller than the sum of its proper divisors 19768.

%t Select[Import["https://oeis.org/A001235/b001235.txt", "Table"][[;; , 2]], # < 4*10^6 && DivisorSigma[-1, #] < 2 &] (* _Amiram Eldar_, Jan 04 2025 *)

%Y Intersection of A001235 and A005100.

%Y Cf. A379466.

%K nonn

%O 1,1

%A _Massimo Kofler_, Jan 04 2025