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A272889 Cubefree taxi-cab numbers that are not squarefree. 0
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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.

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

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.

PROG

(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, ", ")));

CROSSREFS

Cf. A001235, A011541, A067259, A272885.

Sequence in context: A015328 A251970 A270261 * A126104 A031645 A250079

Adjacent sequences:  A272886 A272887 A272888 * A272890 A272891 A272892

KEYWORD

nonn

AUTHOR

Altug Alkan, May 09 2016

STATUS

approved

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Last modified December 2 14:48 EST 2021. Contains 349445 sequences. (Running on oeis4.)