A272889 Cubefree taxi-cab numbers that are not squarefree.

40033, 443889, 1845649, 2048391, 4342914, 5799339, 26122131, 32973759, 41301953, 45882739, 53226297, 54269091, 65272753, 66763333, 70449093, 84637287, 86316741, 90527229, 91140435, 94100426, 104212017, 127396178, 128966383, 131126303, 131997229

Offset: 1

Author

Altug Alkan, May 09 2016

Keywords

• nonn

Comments

There are two versions of "taxicab numbers" that are A001235 and A011541. This sequence focuses on the version A001235.

This sequence lists cubefree taxi-cab numbers that are divisible by a square greater than 1.

Intersection of A001235 and A067259.

Subsequence of A272885.

Examples

			Taxi-cab number 40033 is a term because 40033 = 7^2*19*43.
Taxi-cab number 443889 is a term because 443889 = 3^2*31*37*43.
Taxi-cab number 1845649 is a term because 1845649 = 13^2*67*163.
		

Crossrefs

Cf. A001235, A011541, A067259, A272885.

Programs

PARI

T = thueinit(x^3+1, 1);
isA001235(n) = my(v=thue(T, n)); sum(i=1, #v, v[i][1]>=0 && v[i][2]>=v[i][1])>1;
isA067259(n) = n>3 && vecmax(factor(n)[, 2])==2;
for(n=1, 1e10, if(isA001235(n) && isA067259(n), print1(n, ", ")));