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A343926 a(n) is the least k such that A343443(k) = n or 0 if there is no such k. 1
1, 0, 2, 4, 8, 16, 32, 64, 6, 256, 512, 12, 2048, 4096, 24, 36, 32768, 48, 131072, 72, 96, 1048576, 2097152, 144, 216, 16777216, 30, 288, 134217728, 432, 536870912, 576, 1536, 4294967296, 864, 60, 34359738368, 68719476736, 6144, 1728, 549755813888, 2592, 2199023255552 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The indices for which a(n)=2^(n-2) appear to be A232803. - Michel Marcus, May 05 2021

This is true. We can check it for n <= 10. For n > 10 there are only primes and twice primes in A232803. Any number k > 10 not in A232803 can be factored as k = m*p where m, p > 2 and m >= p. We then have A343443(2^(m-2)*3^(p-2)) = m*p = k. But 2^(k-2) = 2^(m*p-2) > 2^(m-2)*3^(p-2). As m, p > 2 we have 2^(m-2)*3^(p-2) not in A232803. - David A. Corneth, May 05 2021

LINKS

David A. Corneth, Table of n, a(n) for n = 1..3325 (first 52 terms from Michel Marcus).

FORMULA

a(n) <= 2^(n-2) for n>=3.

CROSSREFS

Cf. A025487, A232803, A343443.

Sequence in context: A025489 A160686 A201920 * A223700 A036140 A036138

Adjacent sequences:  A343921 A343922 A343923 * A343927 A343928 A343929

KEYWORD

nonn

AUTHOR

Michel Marcus, May 04 2021

STATUS

approved

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Last modified July 29 14:59 EDT 2021. Contains 346346 sequences. (Running on oeis4.)