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A147802 Least m coprime to 3 minimizing A007947(m(3^n-m)). 4
1, 1, 2, 1, 1, 25, 139, 289, 31, 1, 16096, 49, 7424, 588665, 619115, 83521 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Related to the abc conjecture: Since m is coprime to 3, it is also coprime to 3^n and thus to 3^n-m. Thus A007947(m (3^n-m) 3^n)=3*A007947(m(3^n-m)). See also A143700 for the 2^n analog and A147300 for the general case.

LINKS

Table of n, a(n) for n=1..16.

PROG

(PARI) A147802(n, p=3)={local(b, m=n=p^n); for(a=1, (n-1)\2, a%p|next; A007947(n-a)*A007947(a)<m|next; m=A007947((n-a)*b=a)); b}

CROSSREFS

Cf. A007947, A147300, A143700.

Sequence in context: A156725 A141904 A246072 * A093076 A132454 A182911

Adjacent sequences:  A147799 A147800 A147801 * A147803 A147804 A147805

KEYWORD

hard,more,nonn

AUTHOR

M. F. Hasler, Nov 13 2008

STATUS

approved

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Last modified October 15 05:43 EDT 2019. Contains 328026 sequences. (Running on oeis4.)