

A272892


Taxicab numbers n such that n1 and n+1 are both prime.


2



32832, 513000, 2101248, 8647128, 43570872, 46661832, 152275032, 166383000, 175959000, 351981000, 543449088, 610991208, 809557632, 970168752, 1710972648, 2250265752, 2262814272, 2560837032, 3222013032, 3308144112, 3582836712, 4505949000, 4543936488, 4674301632, 4868489178
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OFFSET

1,1


COMMENTS

Taxicab numbers that are in A014574.
There are two versions of "taxicab numbers" that are A001235 and A011541. This sequence focuses on the version A001235.
First six terms are 2^6*3^3*19, 2^3*3^3*5^3*19, 2^12*3^3*19, 2^3*3^3*7^2*19*43, 2^3*3^6*31*241, 2^3*3^8*7*127.
This sequence contains many terms that are divisible by 6^3 = 216. But there are also terms that are not divisible by 6^3. For example, 166383*10^3 and 351981*10^3 are terms that are not divisible by 216.


LINKS



EXAMPLE

Taxicab number 32832 is a term because 32831 and 32833 are twin primes.


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
p=2; forprime(q=3, 1e9, if(qp==2 && isA001235(p+1), print1(p+1", ")); p=q) \\ Charles R Greathouse IV, May 09 2016


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



