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Revision History for A243405

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Minimum among the numbers p^(n/p), where p is a prime factor of n.
(history; published version)
#8 by N. J. A. Sloane at Mon Jun 16 01:40:41 EDT 2014
STATUS

proposed

approved

#7 by Franklin T. Adams-Watters at Sun Jun 15 02:12:58 EDT 2014
STATUS

editing

proposed

#6 by Franklin T. Adams-Watters at Sun Jun 15 02:12:45 EDT 2014
FORMULA

If n is in A033845, a(n) = 2^(n/2); otherwise a(n) = gpf(n)^(n/gpf(n)). - Franklin T. Adams-Watters, Jun 15 2014

CROSSREFS

Cf. A002581, A092975 (maximum instead of minimum), A033845.

STATUS

proposed

editing

#5 by Stanislav Sykora at Wed Jun 04 21:42:04 EDT 2014
STATUS

editing

proposed

#4 by Stanislav Sykora at Wed Jun 04 21:32:34 EDT 2014
NAME

Minimum among the numbers p^(n/p), where p is any a prime divisor factor of n.

COMMENTS

The setting a(1)=1 is conventional.

a(1)=1 is conventional. Upper bound (for any n): a(n) <= (3^(1/3))^n = A002581^n.

FORMULA

For prime p, a(p)=p.

For n>1: When gpf(n)>3 then a(n)=gpf(n)^(n/gpf(n)); otherwise if n is even then a(n)=2^(n/2); otherwise a(n)=3^(n/3).

PROG

p = factor(n); m = 2^n;

for(k=1, #p[, 1], q=p[k, 1]; q=q^(n\qp[k, 1]); if(q<m, m=q));

CROSSREFS

Cf. A002581, A092975 (maximum instead of minimum).

#3 by Stanislav Sykora at Wed Jun 04 15:39:31 EDT 2014
NAME

allocated for Stanislav SykoraMinimum among the numbers p^(n/p), where p is any prime divisor of n.

DATA

1, 2, 3, 4, 5, 8, 7, 16, 27, 25, 11, 64, 13, 49, 125, 256, 17, 512, 19, 625, 343, 121, 23, 4096, 3125, 169, 19683, 2401, 29, 15625, 31, 65536, 1331, 289, 16807, 262144, 37, 361, 2197, 390625, 41, 117649, 43, 14641, 1953125, 529, 47, 16777216, 823543, 9765625, 4913, 28561, 53

OFFSET

1,2

COMMENTS

a(1)=1 is conventional. Upper bound: a(n) <= (3^(1/3))^n = A002581^n.

LINKS

Stanislav Sykora, <a href="/A243405/b243405.txt">Table of n, a(n) for n = 1..2000</a>

EXAMPLE

a(12)=64 because 2^(12/2)=64 is smaller than 3^(12/3)=81.

PROG

(PARI) A243405(n)= {my(m, k, p, q); if(n==1, return(1));

p = factor(n); m = 2^n;

for(k=1, #p[, 1], q=p[k, 1]; q=q^(n\q); if(q<m, m=q));

return (m); }

KEYWORD

allocated

nonn

AUTHOR

Stanislav Sykora, Jun 04 2014

STATUS

approved

editing

#2 by Stanislav Sykora at Wed Jun 04 14:52:26 EDT 2014
KEYWORD

allocating

allocated

#1 by Stanislav Sykora at Wed Jun 04 14:52:26 EDT 2014
NAME

allocated for Stanislav Sykora

KEYWORD

allocating

STATUS

approved