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A147803
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Least m coprime to 5 minimizing A007947(m(5^n-m)).
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3
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1, 1, 4, 49, 128, 9, 36864, 19332, 4508, 121, 2
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| The minima are given in A147800.
This is related to the abc conjecture: Since m is coprime to 5, it is also coprime to 5^n and thus to 5^n-m. Thus the square free kernel A007947(m (5^n-m) 5^n) = 5 A007947(m(5^n-m)). See also A143700,A147802 for the 2^n and 3^n analogues and A147298 for the general case.
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PROG
| (PARI) A147803(n, p=5)={local(b, m=n=p^n); for(a=1, n\2, a%p|next; A007947(n-a)*A007947(a)<m|next; m=A007947((n-a)*b=a)); b}
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CROSSREFS
| Cf. A007947, A147800 (value of minima), A143700 (analogue for 2^n), A147802 (analogue for 3^n), A147300 (analogue for any number).
Sequence in context: A198384 A136196 A061100 * A112533 A016874 A092866
Adjacent sequences: A147800 A147801 A147802 * A147804 A147805 A147806
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KEYWORD
| more,nonn
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AUTHOR
| M. F. Hasler (www.univ-ag.fr/~mhasler), Nov 13 2008
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