A090857 - OEIS

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A090857

a(n) is the least positive integer such that the integer part of the arithmetic-geometric mean of a(n) and 2^n is equal to 3^n.

1

1, 5, 17, 59, 203, 690, 2308, 7621, 24913, 80794, 260303, 834057, 2660049, 8449715, 26747224, 84407894, 265647824, 834016199, 2612728134, 8168761695, 25494031748, 79434416090, 247130166428, 767788267178, 2382328079245

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..24.

FORMULA

floor( agm(a(n), 2^n) ) = 3^n, for n>=0.

EXAMPLE

a(6)=2308 since floor(agm(2308,2^6))=729=3^6, but floor(agm(2307,2^6))=728.

CROSSREFS

Cf. A090852, A090855, A090856.

Sequence in context: A261515 A171838 A105392 * A287804 A149657 A149658

Adjacent sequences: A090854 A090855 A090856 * A090858 A090859 A090860

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Dec 10 2003

STATUS

approved