

A326234


Numbers n such that N = n^3 is a twin rank (A002822: 6N + 1 are twin primes).


8



1, 28, 42, 168, 203, 287, 308, 518, 1043, 1057, 1512, 1603, 1638, 1680, 1757, 1988, 2905, 3367, 3927, 4018, 4928, 5033, 5145, 5257, 5292, 5432, 5733, 6762, 7182, 7210, 7798, 8715, 10213, 10318, 10668, 10745, 11088, 12243, 13552, 14245, 14588, 14707, 15155, 15323, 15687, 15722, 15757
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OFFSET

1,2


COMMENTS

Dinculescu notes that when n^2 or n^3 is a twin rank > 1 (i.e., in A002822), then n is a multiple of 5, resp. 7. It is unknown whether there exist other pairs (a, b) different from (5, 2) and (7, 3) such that n^b => a  n. (Of course (5, 2k) and (7, 3k) and (35, 6k) is a solution for any k.) See A326233 for the terms > 1 divided by 7.


LINKS



FORMULA



PROG

(PARI) select( is(n)=!for(s=1, 2, ispseudoprime(6*n^3+(1)^s)return), [1..10^5])


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



