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Search: id:A091629
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| 6, 12, 24, 48, 96, 192, 384, 768, 1536, 3072, 6144, 12288, 24576, 49152, 98304, 196608, 393216, 786432, 1572864, 3145728, 6291456, 12582912, 25165824, 50331648, 100663296, 201326592, 402653184, 805306368, 1610612736, 3221225472
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OFFSET
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1,1
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COMMENT
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Sequence arising in Faride Firoozbakht's solution to Prime Puzzle 251 - 23 is only pointer prime (A089823) not containing digit "1".
The monotonic increasing value of successive product of digits strongly suggests that in successive n the digit 1 must be present.
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LINKS
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Index entries for sequences related to linear recurrences with constant coefficients
Tanya Khovanova, Recursive Sequences
Carlos Rivera's Prime Puzzles and Problems Connection, Puzzle 251, Pointer primes
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FORMULA
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a(n) = 2^n*3 = product of digits of A091628(n).
a(n)=6*2^(n-1) . a(n)=2*a(n-1), n>1, a(1)=6 . G.f.: 6x/(1-2x). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 23 2008]
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EXAMPLE
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a(1) = 2*3 = 6.
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CROSSREFS
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Cf. A089823, A091628, A091630, A091631, A091632.
Similar to A003945, A007283, A042950, A058764, A087009.
Sequence in context: A090765 A160728 A082505 this_sequence A089529 A001766 A110959
Adjacent sequences: A091626 A091627 A091628 this_sequence A091630 A091631 A091632
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KEYWORD
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base,easy,nonn
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Jan 24 2004
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EXTENSIONS
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Edited and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Feb 07 2004
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