

A074811


Least k such that prime(k) >= k*tau(k*n) where tau = A000005.


0



1, 1, 1, 181, 1, 1061, 1, 1061, 181, 1061, 1, 40123, 1, 1061, 1061, 6473, 1, 40123, 1, 40123, 1061, 1061, 1, 1617211, 181, 1061, 1061, 40123, 1, 1617211, 1, 40123, 1061, 1061, 1061, 10553429, 1, 1061, 1061, 1617211, 1, 1617211, 1, 40123, 40123, 1061, 1, 69709687
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OFFSET

1,4


COMMENTS

Listed terms are = 1 or are primes.
a(n) = 1 iff n = 1 or n is prime.  Bernard Schott, Apr 10 2020


LINKS

Table of n, a(n) for n=1..48.


PROG

(PARI) a(n)=if(n<0, 0, my(s=1); while(prime(s)<s*numdiv(s*n), s++); s)
(PARI) a(n)= my(k=1, p=2); while(p<k*numdiv(k*n), k++; p=nextprime(p+1)); k; \\ Michel Marcus, Apr 05 2020


CROSSREFS

Cf. A000005.
Sequence in context: A177327 A236235 A225349 * A036200 A253432 A218977
Adjacent sequences: A074808 A074809 A074810 * A074812 A074813 A074814


KEYWORD

nonn


AUTHOR

Benoit Cloitre, Sep 08 2002


EXTENSIONS

More terms from Jinyuan Wang, Apr 05 2020
Name corrected by Bernard Schott, Apr 10 2020


STATUS

approved



